Must Move Air at Right Angle

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Joined: Mon Jul 15, 2019 1:47 pm

Must Move Air at Right Angle

Post by sandpiper » Mon Jul 15, 2019 1:59 pm

I am trying to resolve a difficult airflow problem in a Desktop computer. If there was plenty
of room in the tower, I would use a standard 80mm fan and a duct similar to this one: ... _Duct.html

Space is very limited, so the best choice to move air at a sharp right angle (90 degrees) is
a centrifugal or squirrel cage fan like this one: ... B00HWZ5XGC

Amazon lists many centrifugal fans. They provide the overall fan dimensions, but they
do not provide info about screw hole spacing. I could spend several hours in my shop
designing and building an 80mm adapter for any centrifugal fan.

I tried to find dimensional diagrams for a few of the centrifugal fans listed by Amazon.
No luck. Should I buy a centrifugal fan and build an adapter, or is there a factory made
adapter or fan that fits a standard 80mm square mount?

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Janitor Tzap
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Re: Must Move Air at Right Angle

Post by Janitor Tzap » Mon Jul 15, 2019 7:05 pm


Without seeing your computer case, and what it is that your trying too cool.
I and others here, would have a difficult time trying to recommend something.

If you can please post some pictures here of the case, and the insides of the case, with the side panel of the case off.
That would help, so we can then figure out what sort of fan/blower would work out best for you.

Signed: Janitor Tzap

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Re: Must Move Air at Right Angle

Post by sandpiper » Tue Jul 16, 2019 1:21 pm

I read somewhere that a "generation" for personal computers is about 18 months. If that's
true, I'm several hundred years old! I started building primitive computers when they were
a grid on a board with discrete diodes, transistors, and resistors.

This cooling problem was created by my 13 year old nephew. He wanted to build his first
Desktop. I agreed to pay for the build if he followed my instructions. I created a step-by-
step set of instructions with many images and a video. Over the years my nephew has
watched me build screaming fast Desktops, so my instructions for his first build were

There are two options to fix this newbie created Desktop. Junk several of the components
and rebuild, or add some additional cooling. I've used centrifugal fans in other projects,
but not in a Desktop computer. It's definitely not the best solution, but my nephew is
very upset that his creation has problems.

A few hours ago I figured a way to use a high speed 80mm computer fan with an airflow
hood I can build in my shop. It may or may not resolve the cooling problems with my
nephew's creation. Can't use ducting because of space limitations, but a hood can be
made small enough to fit.

If it works, I will return to this thread and post the results with images.

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Re: Must Move Air at Right Angle

Post by haklesup » Wed Jul 17, 2019 9:38 am

In the tightest areas, one solution is to use a heat pipe to move heat to an adjacent area where a large fin and fan assembly can fit. There are many many configurations of CPU coolers many with heat pipes, right angles, pancake and other configurations, it may take some time to parse through an image search to find just the right one. A water block and recirculator are also fun projects and need not be expensive or difficult if you don't mind a little ugly. An automotive heater core is cheap and a water pump you may have in your scrap box. A water block to put in place of the heatsink also need not be expensive online all that's left are some hoses.

All else fails, just mount the fan outboard on the case and pump room air in at a rate as high as you can. hard to give specific ideas without seeing.

Last year my PC was crashing oddly and breathing heavy, turned out to be dust clogged CPU cooler allowing the PC to get too hot. That machine has well exceeded 18 months by 3 or 4x. At some point PCs got good enough and people started spending on phones instead, now PCs last a lot longer but phone replacement at 18 months is realistic.

You may need to get a 3D printer for this one (finally some justification?)

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