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jsncrs
DYEL


Registered: 01/16/14
Posts: 1,170
Loc: Mars
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Blower for Flow Hood? Help!
#21014274 - 12/22/14 09:10 PM (9 years, 4 months ago) |
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I'm planning on building a flow hood. Looking at buying a 64cm x 32cm HEPA Filter, rated at "99.99% Efficiency, .3 Micron @ Rated Air flow 600 m3H".
Can someone tell me what specs I should look for in a fan to achieve laminar flow? I'm shit at maths
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TheMustardTiger


Registered: 08/19/13
Posts: 4,700
Loc: Sunnyvale Trailer Park
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Re: Blower for Flow Hood? Help! [Re: jsncrs]
#21014322 - 12/22/14 09:21 PM (9 years, 4 months ago) |
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Dilated
KB Cubensis Fanaticus



Registered: 03/28/14
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jsncrs
DYEL


Registered: 01/16/14
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Loc: Mars
Last seen: 3 years, 10 months
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Quote:
MustardTiger66 said: http://www.shroomery.org/forums/dosearch.php?terms=blower+for+filter
Use the search function.
Spent the last hour doing just that. There appears to be too many variables in every post I've read, different size filters etc. Gets quite confusing, which is why I posted this thread.
I've attempted to do the math myself, just wanted someone to check over it...
The filter I've found is in metric, the only fan calculation guide I found is imperial, so..
Filter:
64cm (2.09ft) x 32cm (1.04ft)
2.09 x 1.04 = 2.17 ft squared
Multiply the required air speed (100 ft/min) with the area of your filter
100ft/min x 2.17 ft squared = 217 ft cubed/min
(I saw a note from RR advising that not all fans perform at 100%, and to add between 10% and 20% to the final number)
so, the final number comes out to about 250cfm.
Does this calculation look correct?
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TheMustardTiger


Registered: 08/19/13
Posts: 4,700
Loc: Sunnyvale Trailer Park
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Re: Blower for Flow Hood? Help! [Re: jsncrs]
#21014455 - 12/22/14 09:51 PM (9 years, 4 months ago) |
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Seems about right to me. Even if you can ball park the calculations you'll be fine. If you get a motor that is too powerful, you can stack pre-filters or buy a motor speed controller and play around with it until you hit the sweet spot.
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jsncrs
DYEL


Registered: 01/16/14
Posts: 1,170
Loc: Mars
Last seen: 3 years, 10 months
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Quote:
MustardTiger66 said: Seems about right to me. Even if you can ball park the calculations you'll be fine. If you get a motor that is too powerful, you can stack pre-filters or buy a motor speed controller and play around with it until you hit the sweet spot.
Awesome, thanks mate I've been reading up on this shit all day. Is there any way to test whether the flow is laminar or turbulent? most threads I've come across say that a number of DIY flowhoods actually have turbulent flow, and that they're basically useless.
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TheMustardTiger


Registered: 08/19/13
Posts: 4,700
Loc: Sunnyvale Trailer Park
Last seen: 6 years, 8 months
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Re: Blower for Flow Hood? Help! [Re: jsncrs]
#21014486 - 12/22/14 09:58 PM (9 years, 4 months ago) |
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Hold a lit cigarette lighter a couple of inches away from the filter with the motor running. Laminar flow should bend the flame at a 90 degree angle without extinguishing it. Of course, when you're doing sterile work you'll want that dialed down a tad, but for the purposes of checking the flow, the lighter trick works well.
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jsncrs
DYEL


Registered: 01/16/14
Posts: 1,170
Loc: Mars
Last seen: 3 years, 10 months
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Quote:
MustardTiger66 said: Hold a lit cigarette lighter a couple of inches away from the filter with the motor running. Laminar flow should bend the flame at a 90 degree angle without extinguishing it. Of course, when you're doing sterile work you'll want that dialed down a tad, but for the purposes of checking the flow, the lighter trick works well.
Perfect, think I've got it all under control now, thanks again man!
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TheMustardTiger


Registered: 08/19/13
Posts: 4,700
Loc: Sunnyvale Trailer Park
Last seen: 6 years, 8 months
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Re: Blower for Flow Hood? Help! [Re: jsncrs]
#21014520 - 12/22/14 10:04 PM (9 years, 4 months ago) |
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Quote:
jsncrs said:
Quote:
MustardTiger66 said: Hold a lit cigarette lighter a couple of inches away from the filter with the motor running. Laminar flow should bend the flame at a 90 degree angle without extinguishing it. Of course, when you're doing sterile work you'll want that dialed down a tad, but for the purposes of checking the flow, the lighter trick works well.
Perfect, think I've got it all under control now, thanks again man!
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99.99
Stranger


Registered: 12/22/14
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Bought mine at Home Depot several weeks ago tested it buy leaving petri dishes open for 12 hours two weeks no contamination

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