Why does Negative Air Pressure = DUST ?

[VBboy]

People say that if you have more air getting blown out the case than coming in, that amounts to negative air pressure which causes dust to be collected in the case. Why?

If you have an equal amount of air going in as coming out, won't you still have all that dust blown into the case?

Help me

 

[Sundog]

<< If you have an equal amount of air going in as coming out, won't you still have all that dust blown into the case? >>


No, typically if people are concerned about dust and go for positive air pressure they will have filters on the incoming air. Filtered incoming air and positive/neutral air pressure equals much cleaner case interiors.

Negative air pressure will mean that you are pulling in unfiltered air through every crack and crevice in the system, including through components like floppy drives.

 

[VBboy]

Thanks, Sundog. I understand that air thing now.

Hey, you look cute, wanna go out?

 

[WarCon]

I wouldn't be so sure that Sundog is a girl.
I mean what self respecting girl would have a mini me.............

 

[Jhhnn]

Kinda like what Sundog said, except that without filters there's really no diff- negative pressure pulls unfiltered air thru every opening, positive pressure pushes unfiltered air thru every opening..... Six of one, half a dozen of the other....

 

[Thooor]

What do you mean without filters there is no diff?
Explain

 

[VBboy]

Thooor -

<< What do you mean without filters there is no diff?
Explain >>



You mean pleaseexplain

It means that if you don't have filters on your intake fans, the fans will be pulling in unfiltered dusty air, same as the air being pulled in from other case openings.

So as long as I have filters on the other two large openings on the side of the case, I should be fine...

 

[Mday]

1: a case is not air tight.
2: dust particles are very small.
3: your case has slits, cracks, holes
4: slits, cracks, holes in your case allows air to move
5: dust is airborne before settling
6: having fans only pull air out creates an area of low pressure relative to your room
7: areas of high pressure generally moves into areas of low pressure
8: 7 leads to air from your room going inside your case as per 4.
9: very fine dust gets into your case as per 2, 5, and 8.

 

[Mday]

what happens if you make your case air tight, and only exhaust air?

when you turn your computer fans on, all the air escapes. without air for heat to transfer to, your components get VERY HOT. then your computer dies. and your fans turn off. then air reenters the case from the fan openings. if you computer works, the cycle repeats.

if you have more air out than in?

the low pressure inside will draw air from the higher pressure outside through the intake fan opening, effectively making the intake fans more "efficient" hehehe...

 

[CStroman]

Something I have always wanted to try is to make a completely airtight case. I would cool the interior air with heatsinks on peltiers and the whole thing would have to be dehumidified before sealing.

 

[VBboy]

CStroman,

How are you going to get the heat off the peltiers? They will get extremely hot on the other end, and will require a lot of cooling, probably as much as the CPU to begin with. I think "airtight" is something you want to avoid with a PC.

1. Need to cool hard drives
2. Need to remove the head from CDROMs and CDRWs
3. Need to remove the heat from the videocard (GF3Ti = smoking hot)
4. Need to remove the heat from the chipset
5. Last but not least, the heat from peltiers...

Not gonna work

 

[CStroman]

I've seen people put heatsinks on both sides of the peltier. The hot side of the peltier would be outside the case, and the air going through the heatsink on the inside of the case would be cooled.

 

[Jerboy]

<< I've seen people put heatsinks on both sides of the peltier. The hot side of the peltier would be outside the case, and the air going through the heatsink on the inside of the case would be cooled. >>



If you're gonna do that, just air condition the whole friggin PC.

Get a window mount A/C, vent it into cardboard box and operate a PC inside the cardboard box.

 

[p3z]

when you have positive pressure the air is directed in from where ever your fan is, rather than being sucked in from all the cracks. When air is being sucked in from the cracks it's more likely to suck up dirt from the floor and stuff.

 

[CStroman]

<< If you're gonna do that, just air condition the whole friggin PC.

Get a window mount A/C, vent it into cardboard box and operate a PC inside the cardboard box. >>



That's not airtight.