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gramsp
Magic Bean Buyer


Registered: 02/02/14
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Laminar flow hood questions
#23186028 - 05/03/16 07:33 PM (8 years, 8 months ago) |
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I have a 24" x 24" HEPA filter here which is rated at 1.4 in w.g. I can't seem to find a blower anyhwere powerful enough to deliver 400cfm at ~1.5" w.g. Do you guys have any suggestions of what to do?
Here is the filter I have: http://www.ebay.com/itm/331788896618?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
much thanks grampy
-------------------- Start here. It is the best $9 you will ever spend, and an absolute must for the first-time grower.
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RogerRabbit said:
Before you tell us to go to science class(I have two engineering degrees-do you?), you should go back to second grade to learn the difference between a whole and a hole.
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sdlocalkid85
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Re: Laminar flow hood questions [Re: gramsp]
#23186342 - 05/03/16 08:47 PM (8 years, 8 months ago) |
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go to greners.com and look at inline fans. they have all different CFM fans and I know you can match cubic feet per minute with the filter. I used a squirrel cage fan i found at a hydro store. they work really well but are kinda loud
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mushpunx
Fungus Punk



Registered: 04/20/14
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http://www.fungi.com/product-detail/product/universal-blower-1040-cfm-8-sp.html
This is a universal blower, will work with filters up to 24 x 36". You would have to power it down / block some of the blower intake but you can use it.. FP recomends it for 18 x 24 up to 24 x 36.
I would try to find it somewhere else though FP is kinda high.
I have an 18 x 24 and I use a 549CFM blower. Its a little too small for a 24 x 24. So maybe try looking for one in the 750-900CFM range.
Go with the squirell cage blower over inline its easier to mount IMO.
Also since you bought the deep filter you will want to use a 12" deep plenum at minimum
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gramsp
Magic Bean Buyer


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Re: Laminar flow hood questions [Re: mushpunx]
#23189570 - 05/04/16 06:13 PM (8 years, 8 months ago) |
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I could buy a 750cfm fan on ebay for around $100. None of these hydroponics sellers seem to have the spec sheets for their blowers which show the relationship between filter output and static pressure.
I contacted one seller who was selling a 1080cfm blower. He quoted these specs:
CFM --- Pressure (pa) 0 --- 600 147 --- 480 221 --- 400 294 --- 350 441 --- 210 589 --- 50 1080 --- 0
Which would not give enough flow to my 1.4" w.g. filter. I need a bower that provides 400cfm of flow at 350Pa, but this just seems like a huge amount and is really hard to find a blower that meets these specs.
Thank you for the info.
-------------------- Start here. It is the best $9 you will ever spend, and an absolute must for the first-time grower.
How Frank gets things done
Learned the basics? Read this next (Frank's Tips & Tricks)
RogerRabbit said:
Before you tell us to go to science class(I have two engineering degrees-do you?), you should go back to second grade to learn the difference between a whole and a hole.
RR
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mushpunx
Fungus Punk



Registered: 04/20/14
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Re: Laminar flow hood questions [Re: gramsp]
#23189673 - 05/04/16 06:43 PM (8 years, 8 months ago) |
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You need a blower that pushes at minimum 400CFM @ 1.2 SP for laminar flow with filter face that is 24 x 24" , thats correct.
My blower is 549CFM @ free air and pushes about 300CFM at 1.2 SP. You only need a blower that is a little more powerfull than mine, that should give you a good idea of what size blowers to start looking at. 400CFM at 1.2 sp isn't really that powerfull of a blower
Like I was saying, you can always use a blower that is too strong and power it down, like the one I linked you to.
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gramsp
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Re: Laminar flow hood questions [Re: mushpunx]
#23189993 - 05/04/16 08:00 PM (8 years, 8 months ago) |
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Great info, thank you. So you think the spec sheet this eBay seller sent me is incorrect?
I didn't think it should be, but when I look at spec sheets many of them don't even list pressure more than 0.8". Would I be able to buy a blower in the 850cfm range and assume I'm safe?
-------------------- Start here. It is the best $9 you will ever spend, and an absolute must for the first-time grower.
How Frank gets things done
Learned the basics? Read this next (Frank's Tips & Tricks)
RogerRabbit said:
Before you tell us to go to science class(I have two engineering degrees-do you?), you should go back to second grade to learn the difference between a whole and a hole.
RR
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mushpunx
Fungus Punk



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Re: Laminar flow hood questions [Re: gramsp]
#23190043 - 05/04/16 08:11 PM (8 years, 8 months ago) |
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Quote:
gramsp said: Great info, thank rudyou think the spec sheet this eBay seller sent me is incorrect?
I didn't think it should be, but when I look at spec sheets many of them don't even list pressure more than 0.8". Would I be able to buy a blower in the 850cfm range and assume I'm safe?
Honestly Im not sure. I would assume it works like that but I dont know
.8 should be high enough to make an educated guess though. My blowrr pushes 360CFM @ .8sp , and based on the other incriments you can estimate it pushes a little over 300CFM @ 1.2sp
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Myxomycota
Stranger


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Re: Laminar flow hood questions [Re: mushpunx]
#23190195 - 05/04/16 08:50 PM (8 years, 8 months ago) |
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Hi! Here is a link to my build I just finished: My hood
Might give you some inspiration. I've got a 12*12*24 inch filter at 1.2 w.g. I picked up a anemometer to look at the out put and i'm getting 1 m/s air speed out the final stage filter. This being said, it was a hydroponics brand of inline blower, so it didn't come with a spec sheet, and the manufacturer couldn't provide one. When I was putting it all together, I went through a phase where I thought I should have gone with a stronger blower; I even bought one, but it ended up being to big for my box. That was before testing the final output, which ended up being greater airspeed than is required, so the bigger blower sits in the garage now.
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maddchef
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Re: Laminar flow hood questions [Re: mushpunx]
#23190200 - 05/04/16 08:51 PM (8 years, 8 months ago) |
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Keep in mind though not all blowers are created equal. Don't just say fuck it and grab one slightly more powerful.
SOme drop more than others at pressure. It has to do with other factors such as is it a straight blade bloswer or which way the fins curve along with more technical stuff about the blower that I have no clue about. But 2 different fans both rated @ 500 cfm free can have drastically different outputs @ 1sp
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mushpunx
Fungus Punk



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Re: Laminar flow hood questions [Re: maddchef]
#23190516 - 05/04/16 10:28 PM (8 years, 8 months ago) |
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Quote:
maddchef said: Keep in mind though not all blowers are created equal. Don't just say fuck it and grab one slightly more powerful.
SOme drop more than others at pressure. It has to do with other factors such as is it a straight blade bloswer or which way the fins curve along with more technical stuff about the blower that I have no clue about. But 2 different fans both rated @ 500 cfm free can have drastically different outputs @ 1sp
Yea see this is what I wasn't sure about and its definetly the reason you gotta see the blower specs.
Really glad you chipped in on this
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camplo
Freedom!


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Re: Laminar flow hood questions [Re: mushpunx]
#23190705 - 05/04/16 11:44 PM (8 years, 8 months ago) |
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I ain't the man on the topic, was sharper on the topic when I was actually building mine, which is 24x24. I am under the impression that your average squirrel cage blower rated 1/2hp or higher will be plenty for 24x24. I run mine at its highest speed and a lighter will not stay lit in its flow. nothing in the box is sealed so I know the blower is overkill.
 I paid 35 bucks for that blower (1/2hp) off of craigslist, someone pulled it from a house furnace. I have another one I paid 25 bucks for that is looks almost new, that someone pulled off of a smoker...also craigslist..
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