Rob Wissmann

I guess I make air cleaners now. Visit for prebuilt pc-fan corsi-rosenthal boxes and kits. @robwiss and threads

[Rob Wissmann @robwiss]

A new pinned tweet -- all filter testing I've published to date.

First, the test chamber write-up.
https://t.co/OoMNRdISWY

[Rob Wissmann @robwiss]

I've written up a more accessible version of the technique I use to perform at-home CADR tests in a test chamber. My current setup is a bit more advanced, it is automated and runs from a raspberry pi. Otherwise, it's the same.

#AirFilterDev

https://t.co/6OIGVv1L8x

[Rob Wissmann @robwiss]

@open_erv I still don’t understand. Couldn’t you look at the realtime spectrum (from the microphone) and figure out the contribution of the motor noise by estimating its frequency? As long as it’s different enough from the fan noise freq, that should work.

[Rob Wissmann @robwiss]

@open_erv Not sure what you mean about needing a dynamic microphone connected to an oscope. Have you tried a phone app like AudioTools RTA or REW on a PC? I have a process for using REW on PC with a dayton audio UMM-6.

[Rob Wissmann @robwiss]

@SolidEvidence I may be able to help. DM me if you haven’t already got it.

[Rob Wissmann @robwiss]

@alvelda @mryoung151 What reason is there to be confident in the IFR? I recall covid initially being thought to have a high IFR, which ended up not being the case.

[Rob Wissmann @robwiss]

@JeromeAdamsMD @_CatintheHat @cleanairkits we’ve come up with innovative purifiers based on PC fans and the Corsi-Rosenthal box’s familiar furnace filters to achieve designs with >300 cfm CADR at <40 dBA (they’re quiet).

[Rob Wissmann @robwiss]

@JeromeAdamsMD @_CatintheHat The Dyson TP0x models are around 90 cfm CADR. It would add about 2 ACH to a standard size living room, falling short of the CDC recommended 5+ ACH.

[Rob Wissmann @robwiss]

@kprather88 Same for me. Thanks Dr. Prather for voicing the truth on masks and precautions. Many have been kept safe because you spoke out.

[Rob Wissmann @robwiss]

@lcamtuf Other programming languages let you shoot yourself in the foot. Javascript is constructed entirely of guns and feet.

[Rob Wissmann @robwiss]

@ArbyCalzony I’m being conservative. There can be a drop going from 1900 -> 2500, depending on the fans and filter area. https://t.co/aVYGOR2Ru2

Also, my experimental method has improved so I really ought to look at those old results again.

[Rob Wissmann @robwiss]

I ran 6 Sickleflow with four Filtrete 1900 16”x20”x1” last night, 300 was my Dust Equiv. CADR number.

[CleanAirKits - Big Cleaning at a Whisper @cleanairkits]

We have "one more thing" this week, a super value to keep families safer just in time for Thanksgiving holidays. Introducing the Brisk Box, a $129 taped CR box kit of 6 SickleFlow fans in precision-cut corrugated panels producing up to 300 cfm: https://t.co/Zicd2kHttu

[Rob Wissmann @robwiss]

@ArbyCalzony I did a similar one once. I would estimate around 400.

[Rob Wissmann @robwiss]

9 @ARCTIChannel P14 fans + 4 @3M Filtrete 2200 20"x20"x1" panels = an absolute UNIT

Noise: 44.5 dBA 🙂
CADR: 556 cfm😮
Power: 11.2 W 😵
CADR/W: 49.6 😵‍💫

#CorsiRosenthalBox
#COVIDisAirborne

[Rob Wissmann @robwiss]

@ParentMishmash A CR box would be preferable. It’s hard for the fan to push air through the unpleated fabric therefore the CADR of this solution will be much, much lower than if furnace filters were used with the same fan.

[Rob Wissmann @robwiss]

@VentiloAngel @dannyashton @Engineer_Wong The better way to measure wattage with the cheap meters (kill-a-watt included) is over the course of several hours. I have found that those measurements give the same result as averaging 60s or so of instantaneous measurements, but ymmv.

[Rob Wissmann @robwiss]

@VentiloAngel @dannyashton @Engineer_Wong I have had a unit with 2 A14 iPPC-3000 running off a 1A supply for 2 years. I think the problem might be something other than the max amps of the supply. Is it 12V?

[Rob Wissmann @robwiss]

@VentiloAngel @dannyashton @Engineer_Wong I have the P3 P4400. Seems like it works.

[Rob Wissmann @robwiss]

@VentiloAngel @dannyashton @Engineer_Wong If you get a kill-a-watt you can see the draw at the wall.

[Rob Wissmann @robwiss]

@VentiloAngel @dannyashton @Engineer_Wong ime the rated amps are for the spike at startup and the draw while running is much lower. You can almost certainly run 4 of those with 2A.

[Rob Wissmann @robwiss]

@VentiloAngel @Engineer_Wong Max is crazy loud, we looked into them. Might improve CADR performance at max.

[Rob Wissmann @robwiss]

@VentiloAngel Cool, like I said, should see no difference. Our filter guards have a very coarse mesh. Can use something like speaker mesh and it still barely impacts cadr.