While pondering buying a HEPA style air filter for my bedroom, I noticed that there wasn't much info on the availability of replacement air filters for many of the units being sold on eBay.
I started looking at general purpose filters and discovered tests had been done on various household materials to determine their effectiveness as filters for emergency mask use.
Some of the most effective filter materials were paper towels, coffee filters and other similar random-lay wood fibre materials.
Research suggests that standard kitchen paper towel may be capable of filtering around 95% of 1 micron and larger particles. Given that dust tends to range from 1-100 microns and mould/mold spores are roughly 4-20 microns in size it suggests that a simple piece of kitchen towel or multi-ply toilet tissue could theoretically be used as a cheap disposable filter.
Do not use paper as a fan filter on a computer. They require coarse high airflow filters to keep things like fluff and hair out.
I designed a prototype 3D printed housing (can also be made without a 3D printer) using a standard low power illuminated 120mm computer fan to pull air through a layer of paper towel. It relies on a low volume flow of air to hold the filter in place on a platten and filter it slowly and continuously. It does this with almost no noise and an extremely low power consumption.
This is an ongoing test. Let me know what you think of it.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
I started looking at general purpose filters and discovered tests had been done on various household materials to determine their effectiveness as filters for emergency mask use.
Some of the most effective filter materials were paper towels, coffee filters and other similar random-lay wood fibre materials.
Research suggests that standard kitchen paper towel may be capable of filtering around 95% of 1 micron and larger particles. Given that dust tends to range from 1-100 microns and mould/mold spores are roughly 4-20 microns in size it suggests that a simple piece of kitchen towel or multi-ply toilet tissue could theoretically be used as a cheap disposable filter.
Do not use paper as a fan filter on a computer. They require coarse high airflow filters to keep things like fluff and hair out.
I designed a prototype 3D printed housing (can also be made without a 3D printer) using a standard low power illuminated 120mm computer fan to pull air through a layer of paper towel. It relies on a low volume flow of air to hold the filter in place on a platten and filter it slowly and continuously. It does this with almost no noise and an extremely low power consumption.
This is an ongoing test. Let me know what you think of it.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
A flat sheet of toilet paper/kitchen/shop paper towel has very small surface compared to hepa filter or even better cylindrical hepa filter making it rather inefficient. Shop vacuum hepa filter costs around 6€ and will last a really long time.
How can I diy 20x30x1 heater air filter for my house? Where do I buy that Material from? If I use a different mater like paper or cardboard will it catch a fire?
You could build it to look like a 110mm film roll, with a fan in the middle, and then a reel-to-reel TP transfer. Drive the spent tube with a wall clock (on the hour output) and overclock the stepper motor that the clock would have run on. Then, you get a gradual, continuous filter media replacement. If you notice it's getting clogged too fast, or you're not getting good economy of your squares you can turn a knob to change the millimeters per day of tissue replacement. At the end, the used stuff is contained in the roll and can be trashed without much disturbance. Move the empty roll tube to the dirty side, and tape the first square of your next roll to it.
All i need to do is keep a fan running and by the end of the weak its full of cat hair
i shouldnt have to ask, but can you please provide a link to the article of this research?
I was going to suggest that you could use it for evaporative cooling with damp paper towel but then I remembered that you are on the Island… Quite humid as I recall!
Make the top the size and shape of your paper. The outlet could be a half-cylinder to direct the air for better circulation. The chamber provides 'translation' space. An interesting project would be to write some software to build the 3D model given those constraints around a well-specified fan… Try asking ChatGPT to write it for you!
I'm picturing a little Arduino device where you mount a whole roll of toilet paper and it motor-feeds the paper squares across the opening once every 24 hours.
I like this, where can I get the model?
Filtering air is all about CFM or volume of air moved… if the force of the fan can't touch the air on the other side of the room then the air on the other side of the room won't get filtered… so the CFM has to match the size of the space… CFM is the main thing. I've tested cheap box fan/merv13 with a Dylos 1100 Pro laser particle counter and it's about 95% as good as a True HEPA filter, but not as good. HEPA filters actually get more efficient the more they are used, the only time you have to change them is if there are smells or bacteria/fungi/mold growing on them. So, small filter like this won't have much effect if there is more volume of polluted air than it can process or reach. A Merv 13 filter on our furnace with just the fan going cleans the air in almost every room in the house better than a HEPA filter in one room… on the Dylos the fine particle reading with the Merv 13 goes down to about 110 (left side reading) and in one room with the doors shut the particles can get down to 25 or even 0. The power and reach of our HVAC system actually works to filter each room pretty well. I did not measure all rooms, however because our house is big and I was busy, just a few rooms. One thing rarely discussed is that VOCs can condense into particulates in real time and create a situation where the filter can not keep up, when this happened when we had too much VOC coming into our house (we had to move due to drug labs next door) we couldn't get the Dylos fine particle reading down below 150-300 (left side reading.) I've been doing a lot of testing and a lot of one on one consulting with top PhD's and experts across science, medicine, and the military about air pollution over the last 12 years. I need a simple circuit for a positive plate to attract the dust from a negative ion generator. I'd like to make a VERY LARGE collection plate (like 5 feet x 5 feet in dimensions.) Then run it with one of those Twin Air Pro ionizers by NaurAir but it looks like they are out of business. The goal is to get a mega amount of negative ions moving the charged particles to the big collector plate. Maybe a small fan to create a light breeze toward the collector plate. I've tested the IQ AIR HEALTH PRO PLUS, the round HONEYWELL, an expensive AirPura with 25lbs of charcoal, and some others… I have TVOC meters and the Dylos 1100 Pro to test with. Even the best consumer charcoal filter only reduces about 9% of the VOCs in a room, but can remove most of the particles.
I think a car cabin filter is ideal for a DIY air purifier.
They are quite cheap (10-20 €/$/£) and are simply really good air filters. These days you can get them with activated charcoal and if you want to be really fancy you can even buy filters with anti-bacterial properties. Those also catch mold particles. A layer of a special polymer seems to do the filtering here.
Now all you need is a simple housing for the filter, 12v computer fans and a powerbrick.
On top of all the good ideas like increase the filtering surface etc… I would also chose a pc fan more oriented toward static pressure.
I demand an update! Did it work the way you want? I could imagine that humidity as well es the filter desolving might be problems. Also i doubt kitchen paper can "hold on" to the filtered particles very good…
Just asking because the company that made my filter unit managed to go bust, and now im stuck with a 400 Euro air filter without filters…
But does it have RGB
I made one about five years ago with two such fans but high speed n wood rectangle self made box with uv led for disinfectant n add filter of ac filter cutout