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tombosley8
Full on... Bossley Baggins



Registered: 10/14/13
Posts: 3,660
Last seen: 6 months, 13 days
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look for a blower that does 340 cfm at 1.3"+ and you should be good but maybe the way you did the math is efficient as well but the difference in blowing ability can drastically change from just a little bit more or less resistance depending on the blower. For example It could go from 400 cfm at 1" to 200 cfm at 1.2". You just want to make sure you can push enough air through at the total resistance of the filter prefilter and 10-20%. Now i'm starting to second guess where that 10-20% should be tacked on. The cfm or the resistance?
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Edited by tombosley8 (09/25/14 01:17 PM)
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Ghatti
Totally not a Federal Agent

Registered: 06/23/14
Posts: 1,733
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So with that filter and allowing for the prefilter should I look for a 400cfm blower or a 400cfm blower at 1SP?
Cause that would mean I'd have to go more towards 450. Is there a formula for determining the drop in cfm when adding 1 sp? So if its not listed on a blower I can calculate it myself.
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tombosley8
Full on... Bossley Baggins



Registered: 10/14/13
Posts: 3,660
Last seen: 6 months, 13 days
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Good question... i'm not sure as it depends on the blower. I would think if you compare with the difference in cfm between the previous data then You could get close. So say it goes from 500 cfm at .9" to 450 cfm at 1" then the next would be around 400 at 1.1". Of course this is not exact so I would overcompensate. Some blowers will start dropping cfm rapidly at those higher resistances. Shoot for the bigger blower and adjust with one of these http://www.ebay.com/itm/Variable-Fan-Speed-Controller-Inline-Duct-Vortex-Blower-Exhaust-Control-1800W-/191063176059?pt=US_Hydroponics&hash=item2c7c40b37b until you bend a flame from a bic at 60 degrees 2 inches from the filter.
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Edited by tombosley8 (09/25/14 01:48 PM)
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Ghatti
Totally not a Federal Agent

Registered: 06/23/14
Posts: 1,733
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So far for daytons at least it only seems to be between a 10-30 cfm drop at 1 sp.
I would imagine it would be more for a cheaper fan. Anywho if I do indeed need something around 450cfm the Fucking price tag on a Dayton is like $175 before tax and shipping.
There are a few in line centrifugal fans for around 75$ but they don't have any specs for under static pressure.
Edited by Ghatti (09/25/14 02:09 PM)
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Ghatti
Totally not a Federal Agent

Registered: 06/23/14
Posts: 1,733
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Re: Flow hood help [Re: Ghatti]
#20617623 - 09/25/14 03:11 PM (10 years, 3 months ago) |
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Seeing as I don't have a stat for how certain fans drop under 1SP, what do you think the safe range would be to buy considering I need 400cfm after the filters?
I am guessing 450-475 but I hate to be too low on this and waste my money.
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Ghatti
Totally not a Federal Agent

Registered: 06/23/14
Posts: 1,733
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Re: Flow hood help [Re: Ghatti]
#20618179 - 09/25/14 04:56 PM (10 years, 3 months ago) |
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Okey doke I think I found something quite suitable for a reasonable price to match the filter I last spoke of
http://m.ebay.com/itm/261599230466?nav=SEARCH
It's a bit overpowered but it shouldn't be much of an issue.
Anyone confirm?
Now I just have to figure out how to wire the Fucking thing without electrocuting myself
Edited by Ghatti (09/25/14 04:57 PM)
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blojo02184
Big Red



Registered: 05/15/13
Posts: 3,527
Loc: Maine
Last seen: 6 months, 21 days
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Re: Flow hood help [Re: Ghatti]
#20618372 - 09/25/14 05:27 PM (10 years, 3 months ago) |
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the description on Grainger says that it pushes way less than you need at that static pressure
http://m.grainger.com/mobile/product/DAYTON-Blower-4C444
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Ghatti
Totally not a Federal Agent

Registered: 06/23/14
Posts: 1,733
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That is for the model they're replacing the one I'm looking at with. The one I'm looking at has been discontinued.
The replacement is 350, the dc'd model is 485.
Edited by Ghatti (09/25/14 05:43 PM)
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13shrooms
Lightning Shaman


Registered: 01/01/09
Posts: 26,719
Loc: IN ETHERS TORSION FIELD
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Re: Flow hood help [Re: Ghatti]
#20618685 - 09/25/14 05:41 PM (10 years, 3 months ago) |
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This thread has been closed.
Reason: OP asked to make it so...
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