Air "Pusher"?
Air "Pusher"?
(OP)
Problem: I have a 20"x16"x7" box with some heat generating radio components inside. The aluminum box is sealed for EMI concerns, but the lack of heat exchange is causing the internal air temperature of the box to get too high, and the components are overheating and failing. As a modification, we installed EMI fan vents, which will allow some air to flow in and out, while keeping the EMI shielding intact. We installed some computer fans on the underside of the EMI vents to induce some air flow, but these are obviously not designed to "suck" air through something akin to an air filter.
Question: do "they" make any low profile fans that are designed to suck air through a filter? Mounting provisions are variable, though right now I'm working with an 80mm bolt hole square (size 6 screws). The reverse is do they make any fans that are designed to push air through a filter, or are conventional computer-type fans the best I'm going to find out there?
Question: do "they" make any low profile fans that are designed to suck air through a filter? Mounting provisions are variable, though right now I'm working with an 80mm bolt hole square (size 6 screws). The reverse is do they make any fans that are designed to push air through a filter, or are conventional computer-type fans the best I'm going to find out there?





RE: Air "Pusher"?
Computer fans have no problems with the holes that come in computer cases, so you've left out a critical part of the problem.
TTFN
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RE: Air "Pusher"?
Here is the link to the EMI vents: http://www.tech-etch.com/shield/8200series.html
Yes, the EMI vents have been added as an afterthought (winging it, as you put it), but the EMI vents are proving to be a pretty good solution. With regular computer fans installed as pushers and pullers, we're getting a 40 deg F drop in temp. What I'm looking for a is a more efficient way to move the air through these EMI vents, given that the % open area is quite small and is hindering airflow.
RE: Air "Pusher"?
You only have a limited set of choices:
> Larger fan
> Lower resistance filter
> Larger overall opening
TTFN
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RE: Air "Pusher"?
Let me ask it a different way: Are there alternatives to conventional (axial) flow computer fans, and what are the trade-offs? I know of centrifugal fans, but I don't know the trade-offs. Any other way to circulate air?
RE: Air "Pusher"?
RE: Air "Pusher"?
RE: Air "Pusher"?
RE: Air "Pusher"?
Finding a fan is usually the easiest part: http://ww
The big question is whether your filter will pass any air with a 4" pressure loss.
TTFN
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RE: Air "Pusher"?
RE: Air "Pusher"?
For those interested, we're going to end up with a combination of centrifugal fans on the inlet side and conventional axial fans on the exhaust, both pushing air through the EMI vents. I've got a call in to the manf of the EMI vents to make sure that we wont be loosing any sheilding effectiveness by axing the dust screen (it shouldn't matter, but better to double check). If the dust screen is non issue, we will cover all vents with wire mesh to guard against FOD.
Thank you to CompositePro, IRstuff, and BM4BRANES. Happy Holidays!
RE: Air "Pusher"?
RE: Air "Pusher"?