DIY air purifier

[Anonymous No.1698091]

I saw some pleb on here recommend the xiamoi air filter as a sort of diy solution, since you can just use the filter cartridge with some sort of fan and not pay for the housing, or something like that. I googled around and found reviews showing the Xiamoi did a terrible job cleaning the air.
The people at Smart-Air seem to have shown that a hepa filter strapped to a fan can perform massively better. If you believe their data, yada yada. Anyway I took some cues from their design and made this monstrosity. Not a real HEPA but it was cheap and was the highest filtration level in the store. Seems to be helping a lot with air quality. Ever since I got a cat my asthma has been fucked. This helped.

Post diy air cleaners and related stuff pls

[Anonymous No.1698094]

>>1698091
Constricted the intake a little because the smart air ppl said it helps create pressure with axial fans. This thing actually moves quite a bit of air through the filter, I'm impressed

[Anonymous No.1698095]

Do women laugh at you when they come over?

[Anonymous No.1698098]

>>1698094
This one looks even dumber. But has an activated carbon prefilter.
>>1698095
My fiance appreciates the improved air quality. Kept getting dusty around here

[Anonymous No.1698108]

>>1698091
How do you heat your place? If you have forced air, the best way would be to have a media air cleaner installed.

[Anonymous No.1698111]

>>1698108
Hot water radiators. No forced air. Landlord pays for the heat tho

[Anonymous No.1698162]

>>1698091
Box fan master race reporting in. Ignore the fact that I should have bought a 20x20 filter plz. I blow this fan directly at my face when I sleep and I never have to blow my nose in the morning.

[Anonymous No.1698176]

>>1698162
>Box fan master race reporting in. Ignore the fact that I should have bought a 20x20 filter plz. I blow this fan directly at my face when I sleep and I never have to blow my nose in the morning.

I have the same setup but with a reusable filter.

[Anonymous No.1698178]

>>1698176
How well does that work for you? These things clog for me about once a month. I'd rather be able to wash it periodically.

[Anonymous No.1698183]

>>1698178
>How well does that work for you? These things clog for me about once a month. I'd rather be able to wash it periodically.

Works alright I guess, I'll just blast it with the hose every few months.

This is the one that I have

https://www.homedepot.com/p/Web-20-in-x-20-in-x-1-in-Eco-Plus-Washable-FPR-4-Air-Filter-WP2020FPR/100067063

[Anonymous No.1698285]

>>1698098
Jade please come back, we miss you.

[Anonymous No.1698290]

>>1698098
Jade, buddy. We miss you

[Anonymous No.1698292]

>>1698098
Jade, hope you're alright

We miss you man

[Anonymous No.1698396]

>>1698098
Jaaaaaaaaaaaaaaaaaaaaaade! Our matrices are boring now.

[Anonymous No.1698675]

>>1698095
>women come over
are you serious?
do you know where you are?

[Anonymous No.1698925]

>>1698285
>>1698290
>>1698292
>>1698396
lmao who the fuck is jade????
my name is dan

[Anonymous No.1698928]

Here is a pic I found of a Xiaomi "diy" setup. Smart air tested their regular one and found it was actually the worst air purifier they'd ever tested :(

[Anonymous No.1699011]

>>1698091
Note that a fan sucking air across a filter will perform better than one trying to blow through a filter.

[Anonymous No.1699352]

>>1699011

Nope -

Axial fans have a weak point around the impeller. But your hand right in front of it and you'll notice little to no wind.

If you try to suction with an axial fan - you'll face significant backflow. What occurs is that a lot of your fans air isn't filtered.

There might be a way to curb that backflow, and if you find it let us all know.

But wait, there's more. Usually, axial fans around the tip of the blade produce a wake vortex - meaning that another source of backflow occurs. Unless you have an axial blades shaped to prevent that backflow, you'll face two significant flows

Source: I make air purifiers

[Anonymous No.1699361]

>>1699352
So its better to blow through the filter than suck through the filter, or are you saying it's a retarded idea in the first place?

[Anonymous No.1699499]

>>1699352
>There might be a way to curb that backflow, and if you find it let us all know.
Does constricting the intake a little like I did in the OP help? What you described is what I imagined SmartAir meant when they said it helps generate more pressure.
>Source: I make air purifiers
So why the fuck haven't you posted any pics or designs? Or do you mean you're like, legitimately a designer for an air purifier company?

[Anonymous No.1699522]

20 x 30 3m 2800 filters

[Anonymous No.1699536]

>>1699499

Well I was DIYing a little too intensely, and I eventually sold the design to a bigger company. I'm like a more fluid dynamic adept Thomas (Smart Air guy - who coincidentally is also an Economist (Im a trained Economist)). They have a condition that I help with a piece of the puzzle that I intensely researched but had little capacity in experimenting due to high R&D costs. I'm currently doing that. Can't really post my pics - cause patent, but I can offer really experienced advice.
--------------------------------------

Yeah, I'd say blow through the filter rather than suck if you are doing it with an axial fan. Do it the other way around if you are using a centrifugal fan. I told you why for the axial fan - there are a host of reasons to suction with a centrifugal fan - but the end result is that they are more efficient and less noisy in suction compared to propulsion.

Not really sure with mixed flow fans - but those things are so inefficient it never really makes sense with them. Mi's air purifiers use a mixed flow + axial fan - but that design just seems idiotic to me flow-wise. Who knows - I haven't seen its CFD so I might be wrong. But those comparison videos don't look good to me.

Smart Air's little side strap really just feeds the backflow back into the suction vortex of the fan. That is to say - little if any pressure is added due to that design (in my experience).

I found little to no velocity improvement on the outlet side with straps. But I noticed when I removed it I had a substantial improvement in CADR (how fast the room got cleaned). I hypothesized its because that backflow helped circulate wind in the room. I then added little flaps that pushed that air to the side, and I noticed a further improvement in CADR.

A big problem with air purifiers is that the little windflow they have isn't enough to properly circulate wind in a room. That backflow is a cheap ticket to doing so. Don't weaken it by putting the straps - help it.

[Anonymous No.1699538]

>>1699352
>full of shit: the post

[Anonymous No.1699539]

>>1699352
>I make air purifiers
With planned obsolescence in mind you fucking fraud.

[Anonymous No.1699544]

>>1699499

But if you got an anenometer - I'd say measure your outflow from the filter side. And then try it without it. If you see any improvement then, I'd say keep it. If you don't chuck it. Its most likely what I said, but I've been wrong many times so don't take my word for it.

Try and get a anenometer meant for low speed winds the wind flow is probably not that high. You'll probably get something rangin from 1.5m/s to .5m/s.

I'm guessing you got the box to reduce noise?
Measure the frequency of the noise - in my experience axial fans produce low frequency noise that can't be easily absorbed (especially by cardboard). Check the frequency and find a suitable noise absorber if you want.

These DIY air purifiers only work because of advances in filtering Pressure Drop - back when this shit was all fiberglass you could probably couldn't clean shit with anything but the most powerful axial fan.

Advances in synthetic filters make this all possible. I'm expecting further advances with the advent of polyacrilonitrile filters and nylon 6 nanofibers - although who knows how long the industry will take to finally integrate these things.

Curious - what are the specs on the fan and the filter?

If you can measure out the speed without the filter with an anenometer. That will give you a rough idea of the amount of pressure you are applying.

1.225*v^2*.5 = Vp

Course its more complicated than that. And don't trust the manufactures CFM / Surface area of fan. You should measure it.

Course the fluid behaves a lot differently the moment a filter is attached - so unless you do CFD you'll have little idea whats happening.

[Anonymous No.1699549]

>>1699539

I assume your talking about needing new filters more frequently than if you just use a centrifugal fan due to the rising pressure drop of the filter as it gets dirtier?

Or are you talking about the need for a pre-filter and the inability of the axial air purifiers to really go through multiple layers of filtering?

Or are you just trolling?

[Anonymous No.1699554]

>>1699539
Oh no - it is because I contradicted you - you child.

Meh; I thought you had insight.

Suction is worse for axial fans because the backflow will mitigate suction to the point that filters can't be used beyond a certain percentage of their dust holding capacity.

Additionally, the CADR is just lower. Of course, this may differ fan to fan. (All I can say is from my experience). I've never actually tried the classic box fan DIY.

[Anonymous No.1699568]

>>1699549
>>1699554
Thanks for reinforcing my point.

[Anonymous No.1700954]

[Anonymous No.1700983]

>>1698091
fun fact: a rug and open window function as a great purifier.

Rugs trap debris which you can then vaccuum. EPA studies show that regular vaccumed carpeted rooms have better air quality than hard surface floors. A rug is great because it traps most of the stuff and you still have the aesthetic of hardwood.

Air purifiers that people use in a home are mostly a gimmick. they simply dont have enough power to rapidly exchange the volume of air needed and filter it. If you have ever been in manufacturing enviornments where 'real' filters are used you will notice they are massive in order to rapidly turn over all the air.

[Anonymous No.1700993]

>>1698675
DIY is an outlier, with a fair bit of boomers and high school dropouts, most of the people here actually get some.

[Anonymous No.1701049]

>>1700983
Industrial spaces are usually massive too and so is the amount of particulates when compared to average house.
Not to mention that bigger purifiers can have surface area of the same order of magnitude as some of the rugs you are speaking about and they FORCE the air flow unlike a rug lying on the floor.
tl;dr
You don't know what the fuck you are talking about.

[Anonymous No.1701053]

>>1699352
>>1699536
>>1699544
>>1699549
>>1699554
>>1700983
you

have

to

go

back

[Anonymous No.1702051]

>>1700983
Pretty sure the hardwood floor I sweep, vacuum and swiffer daily collects the same amount of dust and traps way less long term. And my OP pic of the fan with the filter on it moves quite a bit of air, but that's why I think it's better than a comparable one that cost the same.

[Anonymous No.1702246]

>>1698091

that thing is fucking ugly... you should be embarassed to have that sitting there

[Anonymous No.1702277]

>>1699361
You're not sure if it's better to succ or blow?

[Anonymous No.1702279]

>>1700983
>a rug and open window
You mean a rug instead of drapes or a rug hanged on the wall?

[Anonymous No.1703839]

>>1698091
OP here. Just changed my filter. Fuck was my house dusty. I'm hoping this was like a first purge and that I'll never collect this much shit after just over one month ever again.

[Anonymous No.1703841]

>>1703839
grosssss

[Anonymous No.1703842]

>>1703841
Trying to show how much airflow I was getting. I'll do a sheet of paper test next time, this one seems dumb

[Anonymous No.1703845]

>>1703842
Must be a weird vortex action or something because it almost seems like the flame gets more deflected farther away, at least in the center. There is a dead zone right in the center in front of the "hub" of the fan blade, but there is no noticeable difference in flame deflection when I move side to side or up and down... anyway thanks for reading my blog

[Anonymous No.1703848]

>>1703845
New design doesn't let air pressure escape in front of the filter where the ducting touches it. Sealed up the corners. Also offset the filter an inch so the entire filter can be used instead of the center only. Should give a little less resistance that way. Which is good since I added a pre-filter.

[Anonymous No.1703849]

>>1703848

[Anonymous No.1703850]

>>1703849
No more bungee cord to hold it together

[Anonymous No.1703897]

>>1703848
You can't tell from that pic but it's the dual fan blade model. Might help for this purpose idk. They say it has 15% more airflow than their single blade previous model

[Anonymous No.1703951]

>>1698091
I built this 2-3 years ago.
This is a furnace blower I pulled out of the scrap bin

I only have these 2 pics, its in storage. I hadnt added the control switch or the bottom trim or finished it. when I took the pics.

It pushes a retarded amount of air, I used it when woodworking and it kept the dust down without buying a real dust collector. On full blast it bends and damn near damages the filters and will blow shit out of the garage.

[Anonymous No.1703952]

>>1703951

[Anonymous No.1703954]

>>1703951
I approve of this design.

[Anonymous No.1703957]

>>1703951
>>1703952
wasted filter surface area, waste of 4x4's, electrical fire hazard

[Anonymous No.1703959]

>>1703957
But anon, the 4x4s cost nothing compared to the birch plywood that the top bottom and blower mount consists of.

[Anonymous No.1703961]

>>1703951
Shit that's nice. I've been planning one like that, just don't have much money to put toward it right now. Also don't have a real shop, I have an apartment and hand tools.

[Anonymous No.1704471]

>>1703850
What's the prefilter made of? Carbon?

[Anonymous No.1704620]

>>1704471
It's activated carbon impregnated/coated or whatever. Just the standard Honeywell prefilter you cut to size and wrap around their air purifiers. It's very porous and probably doesn't help with smell much at all. My cat took a dump earlier and it still stank, and the filter is right next to the litter box.

I really wonder how much air Honeywells little one room $60 air purifiers can move compared to my fan thing

[Anonymous No.1705007]

>>1703957
wasted post

[Anonymous No.1706197]

Try adding chlorine

[Anonymous No.1706221]

>>1698091
100% not doing shit

first of all, axial fans arent good at building the pressure needed to overcome the restriction caused by a filter. and better filtration means more restriction.

secondly, those filters are not good at stopping cat dander and will just get plugged with cat hair well before doing any good

[Anonymous No.1706802]

>>1706221
You're wrong though, it's moving a bunch of air, I can feel it from several feet away. Surely it's not super efficient since it is the wrong type of fan for the job, but on my budget it's better than nothing. Cost me $16 and some tape. Has helped my breathing tremendously.

And you don't even know what rating of filter I'm using, how can you say it won't stop cat dander? Even after it got loaded with dust/hair>>1703839 it was still moving quite a bit of air through the filter. Just the fact that it caught all that visible shit that would've been floating around otherwise makes it totally worth it. It's a 1900 btw.

If you don't have any advice on how to make it better, take your arm-chair criticism and shove it up your ass.

[Anonymous No.1707290]

>>1704620
>I really wonder how much air Honeywells little one room $60 air purifiers can move compared to my fan thing
Nowhere close, but dirty air is a finite resource.

Once you clean 90% of the room of 99% of the dust, your air filtration system only needs to keep up with new dust and dust that gets kicked up from things and dust that gets let in when you open a window or open your door. A few Honeywell filters in a couple rooms can do a lot of good but they need to run 24/7 and you need to learn how to prevent creating tons of dust. For example, don't fucking smoke indoors and shake dust off old things outside not inside.

The box fan master race thing will clean a dusty room quicker but the noise is probably not worth it for most people. If you have visible mold growing on your walls you need extreme rapid filtration all the time so these box fan things can help but in a clean house there's very little need for such extreme filtration.

[Anonymous No.1707693]

>>1700954
underrated