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Dust Control ... Air Filters ... another example.

Posted: Mon Jul 02, 2007 3:31 am
by Bluefront
Everyone has a dust problem where his computer is concerned. If your own dust problem is small, or if you have a system that runs without any airflow, you can just wipe the dust off every so often.....maybe just open the side and give the inside a blast of air. But for many of us, the dust situation is so severe, we need to construct our own dust control system. You can start by cleaning the computer room, and installing a better filter in your central HVAC system (furnace). Finish that off with a stand-alone air purifier/HEPA air cleaner in the computer room. Maybe try to keep pets out of the computer room.....not usually possible if you like animals. Finally....if you still have a dust buildup in your computer, you will need to construct a filter setup on/in the computer itself. The idea here for me, is to blow filtered/clean air into the computer to keep it clean, and at the same time do it as quietly as possible. The other way to do this, is to blow air out of the computer, and to place filters over all the intakes (I have tried this negative pressure method, and it works, but not as well). In this thread I'll try to explain how I deal with dust, and how I do it as quietly as possible.


For me this means closing off the front bezel completely.....no airflow inward, or outward. Basically you now have three places for an intake fan/filter....the bottom of the case, the back of the case, or the side cover opposite the CPU heatsink. The reason for this.....you just cannot get a good/big filter behind the front bezel, and have a good/big intake channel. And intakes up front are always audible.....no matter what you do.

You need a big filter with the largest possible surface area. This usually means a pleated paper type, like a furnace filter. If your flat filter is big enough, that's also a possibility. I hardly ever use a HEPA filter. They are too restrictive.

Here's a filter at the rear....

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Here's a bottom filter setup

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And here's a flat filter on the side, a 220mm fan sucking through it.

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They all run clean and quiet, on positive pressure, using fanless PSUs. There are countless ways to add good filtration. But it's a DIY project. You cannot at this time, buy a case with a good filter setup. The little flat filters you slap over a fan.....work, barely. You want a clean case....you have some work to do. As time permits, I'll add links to various projects/related threads. Feel free to add your own dust control solutions.....but keep in mind, what works for you, might not work in a really dusty situation.

More to come.....

More photos of the rear filter setup

More photos of the bottom filter setup

Link to side filter thread/photos

The big rear filter thread

The Cookie Jar PC......My first serious filtering project

Clean that filter...Ralf Hutter's dirty computer photo

Another DIY rear filter setup

A filtered lower intake/HD cooler combo

Filter effects on fan speed

Dust kills computers

A filtered front intake setup (these photos are being moved shortly)

Another rear filter housing for a standard filter you don't have to cut

Newest high performance filter

An easily removable bottom filter housing

My latest/greatest filtered setup

Posted: Mon Jul 02, 2007 4:27 am
by jaganath
BF, in the last picture (side fan) what is the purpose of the clear plastic deflector?

Posted: Mon Jul 02, 2007 4:43 am
by Bluefront
I know many of my setups have techniques not obvious in a photo. So any questions are welcome....

That particular photo shows the rear intake on the right edge. The rear fan in the photo is an emergency exhaust fan that only turns on at temps over about 53C or so. Most of the time it's only an exhaust vent (passive). The deflector eliminates any recirculation of the exhaust airflow, something to avoid in any airflow situation.

Also keep in mind.....heated air (exhaust air) always rises, so it's not a good idea to place an intake over an exhaust of any sort. Exhaust recirculation will result, unless you have deflectors in place. In my projects I'll never have any exhaust below an intake......on the side like the photo, possible recirculation can easily be avoided.

Here's another photo of the bottom filter setup.....the passive exhaust from the rear vent is deflected upward to promote more airflow over the fanless PSU. This deflector is not really necessary, as the intake is nowhere near the exhaust.

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Posted: Mon Jul 02, 2007 6:15 am
by BillTodd
BF,

You have a real dust problem there; I'm concerned for your health :shock: :lol:

Have you concidered electro-static filters? (active ones rather than electret type)

Posted: Mon Jul 02, 2007 7:01 am
by Bluefront
My dust problem is caused by my parrots.....and they are more valuable to me than any computer, so they stay along with the dust problem. My computers stay clean, my house less so. That's the way it is..... :lol:

There are many people who have allergic reactions to pet dust/dander. Fortunately I don't......I have air filters running in several rooms, along with built-in filtering in the cages. And I have tried different electro-static cleaners in the furnace filter. These types always give me consternation....they can catch on fire under the right conditions, and the ones I've used were noisy. They sound like a bug zapper.....no thanks. :(

Posted: Mon Jul 02, 2007 9:37 am
by Bluefront
In This setup you can clearly see one of the techniques I employ, when installing a filter.....one which I consider critical to the airflow and noise. This is a buffer zone between the fan and the filter. It is a technique used in many different applications.....it allows the fan to suck air through the entire area of the filter. If you place a filter right on a fan, you lose this advantage. As far as how big this space must be....depends, on the surface area of the filter, the amount of airflow, etc. I try to use at least 38mm clearance.....but bigger clearances might be better.

Posted: Mon Jul 02, 2007 10:38 am
by BIONIC_EARS
I'm currently reworking my two 100mm fan mounts to add a little extra clearance to the front bezel. I have 3 hard drives, and prefer two front fans, so I don't have other options, but for someone with only 1 or 2 drives in the Solo, the bottom hard drive bays can house a 120mm (or less) fan far behind a front-mounted filter. The side vents in the bezel are more than enough to supply air for 1 fan, and the fan will be deep in the case to minimize noise.

Posted: Mon Jul 02, 2007 3:49 pm
by Bluefront
Some of you may be wondering what a "filter-related" post is doing at SPCR. Well IMHO......If you blow a fan into a case, rather than out of a case, and then attach a large acoustically padded filter housing (like the very first photo), the noise level of your setup will be reduced. Now this is something I cannot prove, but it sure seems that way when I listen to these filtered rigs.

Some of you guys will have to try it out....then report the results. :lol:

Oh...FWIW. Many of my early photos were on Yahoo photos, which is closing. They are being transferred to Photobucket, but the links probably won't work after September, 07. If anyone is interested in a photo with a dead link, just ask. I may be able to post a new link.

Posted: Tue Jul 03, 2007 2:47 am
by Bluefront
Negative pressure cases and filters......Face it. Most computer setups you can buy, and most computers you see on SPCR are running negative pressure. A negative pressure case has more air being blown out, than is being blown in. The result of this......airflow into the case will be through every possible entry point. This includes through the guts of an optical drive, through every I/O port on the MB and cards that aren't plugged in, through every crack and crevice the air can find. Air will always take the easiest entry path.

What this means is that in order to keep the computer clean, you will have to seal every little hole you can find. Then You can put large filters over various vent holes, and expect the air will be sucked through the filter, rather than through an open crack somewhere. This isn't easy.....but can be accomplished with a lot of work. Even then.....sealing will never be perfect. The higher the exhaust fan pressure, the more the dust will try to enter through an open USB port somewhere(for instance).

This is one of the reasons I am now using positive pressure in all my recent projects. You just place a good filter in front of a fan blowing into the case, insuring all the air entering the case will be filtered. Even if the PSU fan is blowing outward, if you have more filtered air blowing inward, your case is running positive pressure, and staying cleaner.

I built negative pressure cases for a long time, and struggled to seal all the cracks.....finally gave up on it. Here's a link to my favorite filtered negative pressure case.

Posted: Wed Jul 04, 2007 3:57 am
by Bluefront
If you are determined to have a front intake with a good filter, there is one available that I can recommend......a Nissan cabin filter #999M1-VP002. You can get these from a Nissan dealer (two per package), maybe on-line. The easiest way to install this filter is inside the case, right up against the front panel......A rear case fan blowing outward will suck right through it. This is a medium restriction filter, and it's sturdy with a plastic frame.

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That's a used one on the left. On the right is a new one with the end piece cut off, to fit in a computer. The second photo shows one up front inside a HP computer. The cut-down size.....183x102x12mm. Now if you need a shorter filter, you can cut off the end piece with a dremel cut-off wheel, remove a section of the filter and frame.....then glue the end piece back on. I've done this many times to fit a particular space....it's easy. I've been using these filters for several years. They can be cleaned with a vacuum (the one in the photo is from a Nissan Xterra, used up). I also use this filter in different applications. Here it is in a lower intake setup...

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If you have a case with a thick enough front bezel, you can place this filter outside the case, behind the front bezel. When you have this filter in that location, the front air intake channel is reduced by 12mm, which may make your intake too restricted.....so be careful if you try this, and measure first. This is a high-quality air filter, much like the 3M Filtrete filters......and it stops dust.

Oh....This filter is also available from Nissan (an early Maxima I think), in a longer length of about 220mm....the other dimensions are the same.

Using a PICO power supply? You can turn the former power supply chamber, into a filtered HD intake chamber. I've got a laptop drive suspended right behind the filter. With this setup you'll need to deflect either the intake or the exhaust airflow to prevent recirculation.

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Posted: Sat Jul 14, 2007 3:24 pm
by Bluefront
Till now I've never recommended a home air cleaner/purifier......mostly because every model I heard was too noisy, even on low speed. Well I can now recommend a Bionaire Permatech #BAP4010. I found one at BestBuy for $150.

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This is a smallish unit, made for a medium sized room. On the low-speed setting, it's quiet enough that it won't bother you at a distance of about 6 feet. The HEPA filter comes out easily for cleaning. The airflow is upward.....so don't expect this thing to act like a fan. One of these in your computer room, might solve your dust/cat hair problem, without touching your computer.

Posted: Thu Jul 26, 2007 2:04 am
by mcoleg
Bluefront, how bulky is that thing? i looked at the h/w/d and it looks smaller than the ones i am using but 8.4" deep is a bit on a fatish side...

Posted: Thu Jul 26, 2007 3:17 am
by Bluefront
It looks like a thin MATX tower computer. And it sits nicely against a wall, out of the way. These things have to be large enough to hold a big filter. Since this particular filter is cleanable, it can be smaller than most. Some of the HEPA units I've tried have great big round filters, and are awkward to place anywhere. This unit will be running 24/7 from now till it breaks..... :D

Posted: Thu Jul 26, 2007 3:50 am
by mcoleg
cool, thanks man.

one more question though, if you don't mind - could you please look at it to see if it can be wall-mounted?

Posted: Thu Jul 26, 2007 4:14 am
by Bluefront
Nope.....no provision for wall mounting. The rear is flat though, so you could rig one up, maybe with a shelf.

Posted: Thu Jul 26, 2007 5:26 am
by Bluefront
You want a floor-fan with a built-in filter? Honeywell HY-048-BP. I found this one at a local Target store...in black. It's reasonably quiet at low speed...no vibrations. The filter is a plastic electro-static type. Of course it's not as good as a HEPA, but it does work. I have used this filter material in a window AC unit.....it's washable.

You can live with this thing. It fits in a doorway nicely. One thing which you won't find in the specs....the remote is infra-red. If you have a learning/programmable component remote, it can control this fan.....one less remote to lose. :lol:

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Oh....it also has an LCD ambient temp display on the top...nice.

Posted: Thu Jul 26, 2007 8:25 am
by mcoleg
thanks Blue...

too bad about the mounts.

i got a panasonic (don't remember the model) and a sharp n60cx (which is real nice). both are pretty darn quiet but not quiet enough to put next to my sleeping mat since they do have tendency to ramp up as soon as any stray speck of dust is detected... or a bad smell... or whatever...

thanks for the tip on that fan. btw, i found it on amazon for a bit less:

http://www.amazon.com/Honeywell-3-Speed ... 833&sr=8-1


whatever i get will be about two feet from my head. that's why i'd prefer the quietest thing i can find... can't sleep well as is :P

Posted: Fri Jul 27, 2007 10:04 am
by Bluefront
I'm doing some cleaning today, replacing the filter in one parrot cage.....about 3-4 months since I replaced this 20x20" furnace filter in my custom-built DIY large-parrot cage, with my built-in dust filtering mod. Parrot dust and computers don't mix well. Best to stop the dust at the source....the first picture shows what I'm having to deal with. That filter was pink to begin with.....these are the first pictures I've shown of this small invention. Feel free to copy.

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The motor to drive the thing is a small bathroom vent fan.....been running for about 14 years.

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Here's a rear view....when re-assembled there's a ply-wood piece that covers the whole channel.

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Here's the intake opening that covers the lower rear of the cage....

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And here's the cause of all my dust problems.....I have a second cage (un-occupied right now) next to this cage.

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The motor is on a timer, and running about 1/2 speed (using a dimmer switch). I did some studies to determine when the bird is the most active, and run the fan accordingly. It runs about eight hours total a day.....and really works as you can see. This is only one part of my dust control solution......big job. When the door over the filter is flipped down, this lower compartment doubles as a storage area.....and there's a slide-out drawer right above it. The two doors came from a kitchen cabinet....the rest was made from scratch.

:lol:

Posted: Fri Jul 27, 2007 12:28 pm
by ishi
My way to keep case dust free:

Microfilter used in car audio setups (for speakers protection).
Very thight mesh and very low resistance for air.

http://img380.imageshack.us/my.php?imag ... 147xi5.jpg

Disadvantages:
I must clean filter every week by vacum cleaner
Advantages:
6 month and case looks like new one :)

Posted: Fri Jul 27, 2007 12:36 pm
by kittle
Thanks much for sharing your pics! Seeing the initial cabin filters and then where you put them in the case finally made sense.

Im going to and see how much cat hair they will keep out of my case.

I assume you sealed your case? ... closed off the front bezel with something? .. if so how to deal with the cdrom/floppy drives? I dont think dust will buildup much.. but long cathair will definately get caught on stuff.

my walking cathair factory has average hair length of about 3 inches...

Posted: Fri Jul 27, 2007 12:46 pm
by ishi
In my case micro filter blocking around 95% of dirt and dust.

If you want to se my setup here is link:

viewtopic.php?t=39033

Posted: Fri Jul 27, 2007 3:20 pm
by Bluefront
kittle.....that is a very tight case in the photo with the filter up front. I had to enlarge the opening behind the filter leading into the front bezel space. There is a fairly large opening at the bottom of the front bezel, so there appears to be plenty of airflow.

That case has no floppy drive.....and one optical drive. I try to seal all the little holes on the sides of the drive. As to the rear of the optical drive.....some silicone rubber sealant, and cloth duct tape do the trick. I also seal around all the card openings and the I/O panel with silicone. Sealing a negative pressure case is no fun, but necessary to keep out the dust, even if you are using a filter.

filter for nsk2400

Posted: Sat Sep 15, 2007 10:37 pm
by Breakout
I've been looking to build a dust filter for an nsk2400.

If you have the 2 120mm side fans blowing in, it looks like you can quite easily construct a filter house for a positive pressure case.

The dimensions of the cabin filters from different cars, you can check at puravent.co.uk
It takes some time browsing the different carbrands & makes but it saves you from going to a shop and measuring.

The cabin filter I found to be the best fit for the side of an nsk2400, is the one for a Ford Transit built from 2000 onwards. It measures 353 x 124 x 25 mm
(outside frame excluding seals and lugs) and has no plastic frame.

I found one for 14 euro in a ford car parts dealer (for the Belgians: fordparts.be in Houthalen), it's the micronAir MP101 (Ford Transit 00->).

Posted: Sun Sep 16, 2007 3:27 am
by Bluefront
Breakout.....if you can, please post a picture of that Ford filter. And do you know what that particular Ford is called in the USA....if it's sold here at all. I've never found a site that listed cabin filter sizes for USA cars. It would be useful.

If I knew the USA model of that Ford, I'll try to get one locally to check it out. Building a filter for the side of a case is easy.....using the aluminum channel kits for window screens, and flat foam filters. I've never come up with an easy way to build a custom sized pleated filter.....it's possible, but difficult.

Oh.....Welcome to SPCR. Only a few people around here use filters on their quiet computers. Any filter information is appreciated by me anyway. :lol:

Posted: Mon Sep 17, 2007 12:38 pm
by Chris Chan
Nope, the Ford Transit isn't sold in the US. Only in Europe and Asia.

Posted: Mon Sep 17, 2007 11:10 pm
by truckman
Bluefront wrote:I've never come up with an easy way to build a custom sized pleated filter.....it's possible, but difficult.
It's possible to special order custom-sized pleated furnace filters, including ones using Filtrete filter material. The Filtrete ones are pretty pricey, but there are other brands that are a lot cheaper. The minimum size for the custom Filtrete filters is 8"x10". I turned up several sources with a Google search.

Posted: Tue Sep 18, 2007 2:42 am
by Bluefront
Heh....I've usually got more time than money, so I'll make a custom filter, rather than order one. The first photo in this thread shows a pleated filter cut out of a large furnace filter. Sealing at the pleats is the hard part. I cut out some thin foam strips, with a saw-tooth edge to match the pleats. The pleat edge of the filter is sealed by this foam. It could be glued together at this edge for the best fit.

nsk2400 filter

Posted: Sat Sep 29, 2007 7:46 am
by Breakout
Hi Bluefront,

Ford Transit is one of the most commonly used vans in Europe but it is not sold in the US, not enough chrome I suppose ;-) .

Alternatively, for an NSK2400 one could use the cabin filter for an Mini (BMW), see here. Height of that filter even fits the NSK2400 better (Transit ones are 2mm to high), the Mini filter is to long for the side of an NSK2400 but since it doesn't use a frame, one could quite easy cut it short along the paper fins (the side piece is detachable), I'll post some pics later.

I didn't find a site that lists cabin filter sizes for USA cars. The only one that I know of is this one. It lists them in mm but you can convert that in inches.

BTW what do you mean with "aluminum channel kits for window screens" (sorry: my English isn't that good), could you post a link ?

Posted: Sat Sep 29, 2007 8:33 am
by Bluefront
This picture shows one of those aluminum screen channel kits.....turned into the frame for a big side filter (partially pulled out). Normally a piece of window screen goes into the frame, but a flat foam air filter also will fit. You get four long aluminum channels, which you cut to size. You also get four plastic corner pieces. It just snaps together. Then you use the supplied rubber channel to secure the filter (or a screen). It's really easy to make a custom-size sturdy flat filter with these kits.....they're cheap at big hardware stores.

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