What is this device attached to aluminium pipe

[bitcoinexplorer]

I was working on finding best solution for my Dash mining equipment coming from bitmain which is similar in shape to antminer s9

Have a look at this video  at 1:01  https://www.youtube.com/watch?v=317wqakIKx8&t=10s

I understand that the pipes used are aluminium pipes and joins as well but i am not able to figure out what is the device attached at end of these pipes and where is the hot air sucked from the anminers going  to

 

Thanks.

[Trinislacker]

The guy xplained it in the video. They are extractor fans. The air is extracted to an elevator shaft.

[ltcsprite]

It's an inline fan with duct reducers attached to it.

Very common in HVAC

[xxcsu]

Commercial Kitchen Exhaust Fan

 something similar to this