Fans, PC cases, some thoughts was Re: Connectors, switches etc.

Dave,List,

Doing it this way you also pull a large quantity of whatever is in
the air through those holes... Right past the drives. Including
dust,swarf,CONDUCTIVE metal particles, etc.

A possibly better Idea is to use positive pressure. The idea is that
you make it slightly harder for the air to get out than to get in.

Put filters over the fans (replaceable/ cleanable filters in common
computer fan sizes are readily available). Have them "suck" outside
air through the filter into the case. This will result in a higher
air pressure within the case compared to the outside air. This
positive pressure means that air will ALSO be "blowing" OUT from any
holes, slits and crannies in the case. Which minimises/prevents the
junk in the outside air from getting into your case.

To ensure adequate airflow you will need to have some planned air
exits. Your holes near the drives are fine. There is a whole science
to determining the ratio of in to out, and designing airpaths that
dont have "eddies" (slow,non, or reverse-moving air). TFAR (That
Feels About Right) techniques will likely work here.

A "remote" (indoor/outdoor type) thermometer placed inside will let
you know if you have enough airflow inside of the box by letting you
see if the temperature inside is rising too much above the
surrounding air temperature...

Hope this helps,

Ballendo

P.S. Don't forget that heat rises. You can take advantage of this
fact to "help" the air move the way you want it to...

Also: Many tower cases have a secondary fan location in the bottom
front.
Use this fan to cool the lower part of the case (PS, and interface
card(s), I/O). Place a "divider" (thin plastic, sheet metal, or even
cardboard between this area and the upper part of th einterior. (From
the power supply location to the underside of the drive bays.) Now a
fan placed where the original power supply was located will have a
relatively straight line path to the holes in the drive covers;
passing quite nicely over your drives along the way! And the "card
slot covers" at the rear can be removed or added to control airflow
in th elower part of the case...

--- In CAD_CAM_EDM_DRO@y..., "dave_ace_me" <davemucha@j...> wrote:
<snip>
One trick I
> learned from computer hard drives, (old 3.5 SCSI drives ran hot) is
> to put holes in the plastic front covers in front of the hard
drive,
> where the Gecko's now reside, and have both fans blow out. A large
> quantity of air will enter through those holes.
<snip>