Best Case/PSU Fan Filter?
Jonathan Appleseed
filters, dryer filters, faucet/door screens, or even women's nylons!
Which would probably be best while maintaining decent airflow?
Spajky
wrote:
>I heard that it's possible to make case/PSU fan filters out of acquarium
>filters, dryer filters, faucet/door screens, or even women's nylons!
>Which would probably be best while maintaining decent airflow?
I use the latest .. :-)))
PS. there is no need for PSU (outakes) fan filter!
--
Regards , SPAJKY ®
mail addr. @ my site @ http://www.spajky.vze.com
3rd Ann.: - "Tualatin OC-ed / BX-Slot1 / inaudible setup!"
Mxsmanic
> I use the latest .. :-)))
The latest what?
--
Transpose hotmail and mxsmanic in my e-mail address to reach me directly.
kony
<ap...@mud.net> wrote:
Best at what? Trapping particles?
That is in direct opposition to maintaining decent airflow,
you'll have to pick what tradeoff you want to make per the
case, cooling needs, and filter area.
Filter area is one place you can really tweak the design.
That is, don't try to just put a fan-sized filter over only
the fan but a larger filter area, MUCH larger... as large as
possible. That will also reduce the cleaning interval if
there's a little extra margin for airflow.
Door screens are far too open to be of much benefit unless
you're only trying to keep larger insects out, they won't
even be effective enough at stopping pet hair. Nylons are
pretty good BUT also clog up faster. Ironically enough the
best filtration method might be having an air cleaner in the
room itself, not in the computer.
Even so, you'll have to decide how much you want to reduce
airflow and how much noise increase you can tolerate.
Consider that good filtration cuts airflow by well over 60%,
and poor filtration, well if it's bad enough it wasn't very
useful, the finer dust particals are the ones that get stuck
in every crevace either way while the larger ones are easy
to just blow out with compressed air.
The last filtered case I built used air-conditioner filter
material, it was a thin foam with plastic cross-braces in it
to aid in mounting it, since it was far larger than the
fans' housings. The borders of the filter panel were sealed
with foam weatherstrip tape on the front bezel.
Next time I build a "from-scratch" filtered solution I'll
use a large 1"-pleated paper fiber AC filter, similar to a
"3M filtrete" product but a generic version that filters
slightly less at about 1/4th the price, making it more
economical to throw away instead of bothering with cleaning.
(I don't think my computers are allergic to anything but
we'll see).
http://www.3m.com/us/home_leisure/filtrete/412_micro.jhtml
Phisherman
wrote:
>I heard that it's possible to make case/PSU fan filters out of acquarium
>filters, dryer filters, faucet/door screens, or even women's nylons!
>Which would probably be best while maintaining decent airflow?
There are many. A furnace filter has good flow, easily cut to size
and inexpensive. I use filters designed for a room air cleaner.
Spajky
wrote:
>Spajky writes:
>
>> I use the latest .. :-)))
>
>The latest what?
(option!)=women's nylons :-)
Mxsmanic
> Best at what? Trapping particles?
>
> That is in direct opposition to maintaining decent airflow ...
Not really. A very closely spaced mesh of extremely fine fibers can
catch a great many particles without having much effect on airflow. If
the filter is a mesh with spacing of 50 micrometres but the fibers in
the mesh are only 10 nanometres wide, you can stop 100% of 50-micron
particles and yet impede airflow by only 0.04%.
This is one reason why I've thought that nylons (stockings) might make
good filter material.
David Maynard
> kony writes:
>
>
>>Best at what? Trapping particles?
>>
>>That is in direct opposition to maintaining decent airflow ...
>
>
> Not really. A very closely spaced mesh of extremely fine fibers can
> catch a great many particles without having much effect on airflow. If
> the filter is a mesh with spacing of 50 micrometres but the fibers in
> the mesh are only 10 nanometres wide, you can stop 100% of 50-micron
> particles and yet impede airflow by only 0.04%.
Not after the 50 micron particles plugged up the 50 micron holes.
That's the problem with uniform, single plane, filters.
kony
<mxsm...@hotmail.com> wrote:
>kony writes:
>
>> Best at what? Trapping particles?
>>
>> That is in direct opposition to maintaining decent airflow ...
>
>Not really. A very closely spaced mesh of extremely fine fibers can
>catch a great many particles without having much effect on airflow.
Untrue.
Person after person has tested this and flow rate with even
a marginal filter is less than 50%. That is, unless you
already had such low flow rate that the measurement method
wasn't accurate down to that level thus extreme margin for
error.
It is certainly possible to still have acceptible flow rate,
I didn't mean to suggest anything to the contrary, BUT the
important distinction there is that requires higher fan RPM,
approaching a less than (very) quiet system. I'd rather
have quiet than dustless if forced to choose.
> If
>the filter is a mesh with spacing of 50 micrometres but the fibers in
>the mesh are only 10 nanometres wide, you can stop 100% of 50-micron
>particles and yet impede airflow by only 0.04%.
That is WAY off, unless of course you are also referring to
a filter surface area much, much higher than fan intake, but
frankly I dont' think it's even possible to achieve 0.04% no
matter how large, even if the entire front bezel were
nothing but a bulbous filter panel. I"m 100% sure it's
impossible as the mounting bracket for the filter alone with
NO filter in it will reduce flow by more than 0.04%.
It's up there past 50% flow reduction typically, but the
filter you mention might be past 80% flow reduction. It's
true that mesh can be very effective so long as you clean it
very frequently, but effective at stopping dust is _always_
going to impede airflow a proportional amount.
>
>This is one reason why I've thought that nylons (stockings) might make
>good filter material.
They do make decent filter material. They also drastically
lower flow rate. Take a pair and put a fan inside then tell
me if it was only 0.04%.
Al Dykes
They all work, the difference is probably how often you have to
change/clean the filter.
I've managed very large systems for many years and they all have
filters in the air intakes. All of the filters have been thick mats,
not paper thin like a stocking. I imagine the depth allows lots of
dust to accumulate with a minimum of airflow restriction.
At home I buy a replacement air conditioner filter for a couple bucks
and cut it into pieces as needed and tape it to the case with a little
duct tape.
--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore.
Dorothy Bradbury
o Airflow resistance rises with filtration level
---- HEPA = sub-micron filtration and thus very high resistance
---- HEPA = high pressure radial (blowers) + 48-55dB(A) + few 10s cfm
o Airflow resistance rises with airflow
---- filter presents 15Pa resistance at low cfm, 45Pa at double that cfm
---- compensating for resistance by a merely faster fan is undermined
Coloco Centres filter via the HVAC plant - so racks don't have to...
o HVAC plant uses huge multi-kW high pressure radial (blower) fans
o Racks then try to keep the top (hot) part of the rack within spec
PCs impose several restrictions on cooling system...
o Fans are Axial -- PCs present low airflow resistance & demand high cfm
---- Axial fans -- small size, shallow depth, low noise, high cfm, low pressure
---- Radial fans -- large size, high depth, high noise, low cfm, high pressure
o Filters are omitted -- filter size limited by fan/case size & use of axial fans
---- Axial fans produce high airflow, but little pressure
---- Filter resistance exceeding an axial fans stall pressure results in zero airflow
PCs impose implementation restrictions on a filtered solution...
o All intake air must come through the filter
---- yet PC storage bays reduce the frontal area for filters
o Intake airflow must exceed exhaust fan airflow
---- positive case pressure prevents air intake thro non-filtered holes
---- again PC storage bays reduce the front area for fans
So there has to be a compromise...
o Dissipation of N watts limited to X temp rise requires a mass of air A
o Filters add resistance, reducing airflow, so increasing temp rise
o Balance via adjustments to filter system
---- increase filter size = less airflow velocity = less resistance
---- crease filter level = less resistance
o Balance via adjustments to cooling system
---- increase fan size, fan depth, fan speed
---- increase fan number re serial operation with exhaust fans
In practice?
o Most PC filters simply stop the fan blades dusting
o They will not prevent skived copper heatsinks from clogging
o They will increase the time between clogging - perhaps usefully
It is simpler to clean the CPU/GPU heatsink once in a while.
This is more of an issue with laptops - which use high density skived
copper heatsinks of low height, low airflow, non self-cleaning designs.
Heatsinks are frankly the sole device affected by "dust bunnies"
o Blow through, large fin, high velocity heatsinks are preferable
o Multi-fin (copper sheet flower) or asterisk (alloy extrusion) work well
Comes down to how much thermal dissipation you have.
o Easy to filter (& cool) a VIA C3 PC quietly
o Harder to filter (& cool) a Dual-Opteron 5-SCSI-RAID Twin-GPU Server
Most filters do merely stop fan blade dusting.
o Yes filters will stop the large particulates
o However higher heatsink fin density is a structure for dust matting
o In laptops fans can be roaring in 6 months from clogged heatsinks
In summary...
o Axial PC fans will lose ~40-60% of their airflow with a clean filter
---- the figure gets worse as the filter clogs, and HDs get hotter
o Fitting 38mm depth fans or larger fans can cause "fan count runaway"
---- velocity does not help -- resistance rises with higher airflow fans
---- area can assist -- it reduces airflow velocity, reduces resistance
---- fan count assists -- it increases fan area, reduces velocity & resistance
If you suffer hayfever, go buy a Honewell HEPA filter unit.
They use near operating theatre quality HEPA filter drums inside, they
are relatively quiet and are a better ROI than trying to filter a PC :-)
--
Dorothy Bradbury
Mxsmanic
> Not after the 50 micron particles plugged up the 50 micron holes.
The assumption is that you'd replace or clean the filters periodically.
No filter is going to let air through once it is clogged with particles.
Mxsmanic
> I'd rather have quiet than dustless if forced to choose.
I'd rather have dustless than quiet. And cool has the highest priority
of all.
David Maynard
> David Maynard writes:
>
>
>>Not after the 50 micron particles plugged up the 50 micron holes.
>
>
> The assumption is that you'd replace or clean the filters periodically.
> No filter is going to let air through once it is clogged with particles.
That statement is a self fulfilling circular argument of the obvious. Of
course it won't let air through 'once it is clogged' but the point was how
quick and easy it is to clog uniform, 2 dimensional, media.
Irregular, 3 dimensional, media trap particles without creating such a
'perfect' occlusion of the porosity and have a larger effective surface
area. Not to mention there are other mechanisms for capturing particles
beyond simply "it won't fit through the hole', such as momentum (direction
change) and affinity.
A couple of common examples being the irregular, random fiber mat in
disposable air conditioning intake filters and the washable 'electrostatic'
filter of the same purpose.
kony
<mxsm...@hotmail.com> wrote:
>kony writes:
>
>> I'd rather have quiet than dustless if forced to choose.
>
>I'd rather have dustless than quiet. And cool has the highest priority
>of all.
Understandable.
Even so, a very course filter that doesn't eliminate dust
but greatly reduces it can still be beneficial. Not
"dustless" but greatly reduced dust levels. It is to a
certain extent the user's choice what to do, providing
they'll willing to make the modifications and/or improvise
rather than just buying the generic littel black plastic
filters with the foam insert that are most commonly sold at
PC parts suppliers. Those things are really horrible for
flow rate, last time I tried to put one of those on a 120x38
mm fan I'd guesstimate the flow was reduced to 20% of it's
former rate.
Dorothy make a good point about the axial fans maintaining
lower pressure. I keep meaning to find the time to hunt
down some really quiet radial or diagonal that're small
enough for PC uses, but if TOO much work goes into it you
might be as well off just dusting out the system every now
and again.
Franc Zabkar
>kony writes:
>
>> I'd rather have quiet than dustless if forced to choose.
>
>I'd rather have dustless than quiet. And cool has the highest priority
>of all.
I have 8 fans in my Athlon box, two in the PSU, one on the graphics
card, two on the HDD, one on the CPU, one at the rear of the case, and
one at the front. Have I missed anything? :-)
- Franc Zabkar
--
Please remove one 's' from my address when replying by email.
kony
<fza...@optussnet.com.au> wrote:
>On Thu, 19 May 2005 06:37:40 +0200, Mxsmanic <mxsm...@hotmail.com>
>put finger to keyboard and composed:
>
>>kony writes:
>>
>>> I'd rather have quiet than dustless if forced to choose.
>>
>>I'd rather have dustless than quiet. And cool has the highest priority
>>of all.
>
>I have 8 fans in my Athlon box, two in the PSU, one on the graphics
>card, two on the HDD, one on the CPU, one at the rear of the case, and
>one at the front. Have I missed anything? :-)
The system that I put the AC filters in the front & side,
has:,
3 x 92mm front case wall intake fans
1 x 80mm rear exhaust fan
1 x 80mm exhaust upper PSU
2 x 80mm & 1 92mm lower PSU
1 x 80mm CPU fan
2 (50/60mm) on-card video fans
1 x 120mm side-panel fan
So that's 12, and if it were a box I were overclocking a
lot, it'd have a mobo VRM fan too. The funny part is I
wasn't even trying to put a lot of fans in it, had simply,
previously optimized each part's cooling before they were
destined to be together as a single system.
Then again it's a full server with 14+ well-spaced bays...
wouldn't be very useful to have a giant case without a way
to cool it if/when full. It's merely quiet, not nearly
silent, makes overlapped lower frequency sounds vaguely like
a WWII bomber. That'd be too loud IMO, if it were a
primary-use "desktop" PC. Without the filters it could
easily be adjusted quieter with similar-if-not-same
resulting temps. That many drives results in a lot of
cables though, more cables makes it more of a pain to dust
out a system if/when filterless.
Dorothy Bradbury
o 172mm & 200mm form factors available
o Big noisy, heavy & expensive are the downsides
o Pressure of a radial fan in the package of an axial fan
You can get a reasonable solution using...
o 172x51mm Comair Rotron in 24V, lowest noise spec, run at 12V
o It will emit a tolerable level of noise, yet maintain good pressure
Ideally fit the PC into a ply/alloy flight case from Ebay:
o Extrusion & butterfly catch for the cover
o Heavy material for low frequency absorption (mass)
o Line with carpet rippled-foam-rubber underlay for high frequency
o Large enough to fit a decent size of filter on
Those cases aren't much - compared to some expensive PC cases.
Easily mount on wheels, use an old cheap PC case as skeleton.
Ensure the large exhaust fan is inset onto a sub panel so you
have a lined rear to absorb the noise - don't mount it on the rear.
Just use an external USB enclosure for removeable media.
USB allows hot plugging so only power up when needed.
--
Dorothy Bradbury
Mxsmanic
> I have 8 fans in my Athlon box, two in the PSU, one on the graphics
> card, two on the HDD, one on the CPU, one at the rear of the case, and
> one at the front. Have I missed anything? :-)
I have only seven; maybe I need to add one.
kony
<dorothy....@ntlworld.com> wrote:
>Indeed the Papst Diagonal Flow (DV) range are good re pressure:
>o 172mm & 200mm form factors available
>o Big noisy, heavy & expensive are the downsides
>o Pressure of a radial fan in the package of an axial fan
Yes I have one of those Papst Diagonals, it is a monster of
a fan and would suck small pets into a system. I don't use
it for PCs at all. It would be nice if there were smaller,
lower torque variants in 120 x (n) size... and perhaps there
are but I've not spent the time hunting them down, and
implementation costs could be quite high compared to bulk
purchases of more commonly available fans.
>
>You can get a reasonable solution using...
>o 172x51mm Comair Rotron in 24V, lowest noise spec, run at 12V
>o It will emit a tolerable level of noise, yet maintain good pressure
We seem to have a lot of the same gear, if you're talking
about one of these Comairs (don't have the model # handy at
present):
http://69.36.189.159/usr_1034/comair1.jpg
I didn't find that 24V fan very quiet at 12V, and it was
starting to stall as originally configured. However, it's
circuit board uses an LM317 linear regulator (I forget the
voltage level it was configured to produce) which can be
adjusted, or better still simply removed and the pads
jumpered such that the fan no longer tries to maintain a
constant RPM but rather varies directly with the input RPM.
Perhaps there are different manufacturing options and not
all have the LM317 in them but I "thought" I recalled their
spec sheet mentioning the consant speed within a range of
varying input voltages.
>Ideally fit the PC into a ply/alloy flight case from Ebay:
>o Extrusion & butterfly catch for the cover
>o Heavy material for low frequency absorption (mass)
>o Line with carpet rippled-foam-rubber underlay for high frequency
>o Large enough to fit a decent size of filter on
>
>Those cases aren't much - compared to some expensive PC cases.
>Easily mount on wheels, use an old cheap PC case as skeleton.
>
>Ensure the large exhaust fan is inset onto a sub panel so you
>have a lined rear to absorb the noise - don't mount it on the rear.
>
>Just use an external USB enclosure for removeable media.
>USB allows hot plugging so only power up when needed.
That is one option though I prefer GbE NAS for supplimental
storage, doubt I'd find it worthwhile to use USB except in
certain backup strategies.
Franc Zabkar
keyboard and composed:
>The system that I put the AC filters in the front & side,
>has:,
>
>3 x 92mm front case wall intake fans
>1 x 80mm rear exhaust fan
>1 x 80mm exhaust upper PSU
>2 x 80mm & 1 92mm lower PSU
>1 x 80mm CPU fan
>2 (50/60mm) on-card video fans
>1 x 120mm side-panel fan
>
>So that's 12, ...
I'm envious.
> ... and if it were a box I were overclocking a
>lot, it'd have a mobo VRM fan too.
I wonder if I can simulate the sound of five additional fans with my
soundcard ...
>The funny part is I
>wasn't even trying to put a lot of fans in it, had simply,
>previously optimized each part's cooling before they were
>destined to be together as a single system.
>
>Then again it's a full server with 14+ well-spaced bays...
>wouldn't be very useful to have a giant case without a way
>to cool it if/when full. It's merely quiet, not nearly
>silent, makes overlapped lower frequency sounds vaguely like
>a WWII bomber. That'd be too loud IMO, if it were a
>primary-use "desktop" PC.
Chances are that the combined thrust would walk it off the desk. :-)
kony
<fza...@optussnet.com.au> wrote:
>On Thu, 19 May 2005 09:35:33 GMT, kony <sp...@spam.com> put finger to
>keyboard and composed:
>
>>The system that I put the AC filters in the front & side,
>>has:,
>>
>>3 x 92mm front case wall intake fans
>>1 x 80mm rear exhaust fan
>>1 x 80mm exhaust upper PSU
>>2 x 80mm & 1 92mm lower PSU
>>1 x 80mm CPU fan
>>2 (50/60mm) on-card video fans
>>1 x 120mm side-panel fan
>>
>>So that's 12, ...
>
>I'm envious.
You'd probably be more envious if you realized just how
little I paid for the case/PSU/fans. Nice set of gear that
only required some metalwork to get the 2nd PSU and filtered
fans implemented.
>
>> ... and if it were a box I were overclocking a
>>lot, it'd have a mobo VRM fan too.
>
>I wonder if I can simulate the sound of five additional fans with my
>soundcard ...
LOL.
>
>>The funny part is I
>>wasn't even trying to put a lot of fans in it, had simply,
>>previously optimized each part's cooling before they were
>>destined to be together as a single system.
>>
>>Then again it's a full server with 14+ well-spaced bays...
>>wouldn't be very useful to have a giant case without a way
>>to cool it if/when full. It's merely quiet, not nearly
>>silent, makes overlapped lower frequency sounds vaguely like
>>a WWII bomber. That'd be too loud IMO, if it were a
>>primary-use "desktop" PC.
>
>Chances are that the combined thrust would walk it off the desk. :-)
>
Naw, I'm all about longevity, could've used fewer fans at
higher RPM but wanted longer cleaning intervals and more
redundancy in case there was a fan failure. Since it has a
couple of fairly important data archives on it in online
form, it seemed prudent to make it at least better than the
box it replaced.
Dorothy Bradbury
> about one of these Comairs (don't have the model # handy
> at present): http://69.36.189.159/usr_1034/comair1.jpg
> I didn't find that 24V fan very quiet at 12V, and it was
> starting to stall as originally configured.
> speed within a range of varying input voltages.
Several versions exist...
o Standard -- fan rpm dependent on voltage
---- even so you need the lowest speed spec 24V @ 12V
---- noise will not be very low, but will work with a filter
o OEM -- some maintain a fixed rpm around a voltage range
---- these are unlikely to provide a suitable solution
Aim for 172mm round over 172x150mm fans:
o 172x150mm fans appear just "flattened rounds" for space
o 172x150mm fans also tend to have higher noise/airflow specs
Many versions - only a few work well at 12V.
>>Just use an external USB enclosure for removeable media.
>>USB allows hot plugging so only power up when needed.
>
> That is one option though I prefer GbE NAS for supplimental
> storage, doubt I'd find it worthwhile to use USB except in
> certain backup strategies.
Removeable optical media I should have said.
Flight case solutions tend to be kept shut, it may be preferable
to keep frequently accessed removeable optical media on a desk.
--
Dorothy Bradbury
jed
I've been reading various other threads @ other forums with the same subject matter, but so far none come close to this!
So what I've garnered so far as the options for PC filtration:
*pantyhose (nylon stockings)
*dryer sheets
*air conditioner filters
*air cleaning/purifying filters
http://www.filtrete.com/wps/portal/3M/en_US/FiltreteUS/Filtrete/
I'm using this case
http://www.silverstonetek.com/products/p_photo.php?pno=cw02&area=usa
I will be modding the 2x 92mm intakes to 120mm...
And cutting an extra 120mm exhaust on the rear of the case lid, in line with the PCI/e slots.
I'll also be fashioning a mounting bracket for my H20-220 edge (AIO rad/res/pump system from swifttech)
This mechanism will be bolted to the back right corner of the case lid, near the water tube holes.
The H20-220 Edge will have 4x GT AP-15* in P+P (possibly with shrouds YTD)
For the 2x intakes I was going to use 2x AP-14 (1450RPM)...
For the exhaust I was going to use 1x AP-15 for the exhaust on the lid (can undervolt), & 1x AP-14 for the other.
Or is it better to play it safe with positive pressure & use 2x AP-15 for the intakes, & 2x AP-14 for the exhaust?
Especially considering I'd only be using filtration material on the intakes...
What filtration material and fan config. do you think is the most optimal?
*this range of fans are universally lauded nowadays for having excellent noise to cfm ratio, whilst still maintain decent static pressure
jed
*Honeywell HEPA filter unit
I like this one actually, because I do have some quite bad allergy problems.
So maybe I can kill two birds with one stone!
jed
> In alt.comp.hardware.homebuilt you write:
> ..
>> What filtration material and fan config. do you think is the most
>> optimal?
>
>> *this range of fans are universally lauded nowadays for having
>> excellent noise to cfm ratio, whilst still maintain decent static
>> pressure
>
> Those were highly recommended to me but I am always
> willing to listen to others with experience.
>
> I've also thought about building a shroud out of
> acoustical ceiling tile to try to soak up most of
> the noise without risking excessive heat buildup,
> but I'm not sure how well that would really work.
>
> Thanks for any insight
MartinM did some exhaustive testing which revealed that the GT's generally are the no.1 noise to CFM.
As always the answer not as simple as that, & depends on your application to some extent.
He's no longer taking fan donations & I forget which round of testing he finished at, but he's no longer test fans.
He's moved onto assessing other areas...
Have at it:
Information/Guides & Reviews/Tests & Galleries - XtremeSystems Forums
http://www.xtremesystems.org/forums/showthread.php?t=202394
Fan Testing Round 4 Complete (Results Summary) - XtremeSystems Forums
http://www.xtremesystems.org/forums/showthread.php?t=259802
Fan Testing Round 6, Potential Fan List/Methods - XtremeSystems Forums
http://www.xtremesystems.org/forums/showthread.php?t=261520
YouTube - Martinm210's Channel
http://www.youtube.com/user/Martinm210
Gentle Typhoon's AP-15 (1850 RPM) - Page 5 - XtremeSystems Forums
http://www.xtremesystems.org/forums/showthread.php?p=4572671#post4572671
Gentle Typhoon Ap-15 Incredible!!! - Page 9 - Overclock.net - Overclocking.net
http://www.overclock.net/air-cooling/661937-gentle-typhoon-ap-15-incredible-9.html#post11154126
Skineelabs I think also has some great methodologies/testing in this area.
Cheers,
Jed
jed
https://groups.google.com/d/msg/alt.comp.hardware.homebuilt/Q_8wKlgc3Zg/ASswnu8YJy0J
thank-you!