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WhAcKeD
Researcher
Registered: 11/24/00
Posts: 307
Last seen: 13 years, 2 months
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Need a Cheap HEPA FIlter for Flowhood
#9284944 - 11/21/08 12:12 PM (15 years, 3 months ago) |
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I'm going to build a laminar flowhood and two air filters. FP has the 12x12's for $90 (for the air filters) and the 24x18 for $160 (for the hood.) Their's are 99.99% efficient and operate .8" static pressure. They also say they are manufactured specifically for this purpose. SHould I just buy them from FP, or is there a cheaper source?
Also, I need a 300+ CFM blower for the hood. Suggestions?
Thanks!
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FooMan
Registered: 02/02/05
Posts: 8,957
Loc: Earth
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: WhAcKeD]
#9285097 - 11/21/08 12:31 PM (15 years, 3 months ago) |
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Check the flow hood build thread in my journal. I have a link to the place I got my filter.
-------------------- Quick WBS Prep
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CheeWiz
Registered: 09/28/08
Posts: 276
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: WhAcKeD]
#9285178 - 11/21/08 12:39 PM (15 years, 3 months ago) |
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Hi: Look on Ebay, the RR site has a link on how the build a Laminar flow unit and in this site they have the latest offering on Ebay. The trick is to go to each seller sites and see what they have that's not listed out right on Ebasy. Myself I got a 24"x48"x 8" filters with a 4"deep pleating for a little over a $100.00 plus shipping that ran me about $50.00 from the east coast. The filter was not being list on Ebay because the seller felt that no one would want something that large(many big sellers list only the things they feel are going to sell to avoided fees to Ebay for something that my not), but did have it listed on his site and I was able to contact him and cut a deal thou Ebay and paid for it using Pay-Pal. Best Wishes; Hipster
Edited by CheeWiz (11/21/08 01:16 PM)
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WhAcKeD
Researcher
Registered: 11/24/00
Posts: 307
Last seen: 13 years, 2 months
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: FooMan]
#9285305 - 11/21/08 12:52 PM (15 years, 3 months ago) |
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Thanks FooMan. In your Flowhood build thread you mention that the air flows a little too fast. Why is this? And what is the cfm rating at .8 static pressure for your blower? Also, two questions on the filter: Can it be 99.97% or must it be 99.99%? And is there any advantage to using a high capacity, 12" deep, filter?
PS, thanks for the tips, Hipster, I'm on ebay right now... :-)
Edited by WhAcKeD (11/21/08 01:01 PM)
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FooMan
Registered: 02/02/05
Posts: 8,957
Loc: Earth
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: WhAcKeD]
#9285417 - 11/21/08 01:07 PM (15 years, 3 months ago) |
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It's faster than the 100ft/ second recommendation that Stamets has. The basic test is to hold a lighter in front of the hood. The flame should bend at a 90 degree angle without blowing the flame out. My hood blows the flame out until after you're about a foot away from the filter, but I haven't had a single problem with contams yet.
People use 99.97 filters. I went with the 99.99% just because it wasn't much more for it. I don't think the high capacity filters would be neccessary for a flow hood. That high capacity flow seems more useful for clean rooms. I went with 6" because 12 is deep and you need room for a plenum and I'm tight on space here.
-------------------- Quick WBS Prep
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WhAcKeD
Researcher
Registered: 11/24/00
Posts: 307
Last seen: 13 years, 2 months
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: FooMan]
#9285663 - 11/21/08 01:52 PM (15 years, 3 months ago) |
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Thanks a bunch FooMan, I ordered two filters: (1) 12x12x6 99.99% wood for the lab/grow room input (which keeps positive pressure in the rooms) and (1) 24x30x6 99.99% wood for my flowhood. I figured I want to be able to inoculate and seal 4 filter patch bags at a time with grain spawn, so this would be about the smallest size I can be comfortable with. So now I need a 500cfm blower.
Will the 8" vortex style that you used be sufficient? I am tempted to go with a 4 speed furnace blower, for $175. It does 510 on the lowest setting, and 1000 on the highest.
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FooMan
Registered: 02/02/05
Posts: 8,957
Loc: Earth
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: WhAcKeD]
#9290051 - 11/22/08 02:27 AM (15 years, 3 months ago) |
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Quote:
WhAcKeD said: Will the 8" vortex style that you used be sufficient?
I just got the 8" because I knew it had more than enough flow for my 12 x 24" filter. I could have probably gotten away with the 6" model. Your filter is a lot bigger, so I would probably go with more cfm.
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WhAcKeD
Researcher
Registered: 11/24/00
Posts: 307
Last seen: 13 years, 2 months
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: FooMan]
#9290231 - 11/22/08 03:49 AM (15 years, 3 months ago) |
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Hmmm. Interestingly, I just noticed that the static pressure on the filters I bought is pretty low - around .5" @ 100cfm - so I think the furnace blower is way too big - it does 1100 cfm on the lowest setting at that static pressure - even if the prefilter is taken into account (.2") the blower's output is still 1000cfm. But I can't seem to find any info for the VLF-8, the 8" blower that fooMan has, so I'm not sure if its 745cfm rating will drop below the 500 that I need at .7" static pressure. FooMan?
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WhAcKeD
Researcher
Registered: 11/24/00
Posts: 307
Last seen: 13 years, 2 months
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: WhAcKeD]
#9334059 - 11/29/08 08:00 PM (15 years, 3 months ago) |
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I'm still looking for performance data for that ValueLine 8" so if anyone has it please post it. I need the output at .9" static pressure. Interestingly, I just learned that you need to take air density and temperature into account, ie at 5000' static pressure is effectively 1.2 times that of sea level; .75" becomes .9".
Edited by WhAcKeD (11/29/08 08:09 PM)
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trich_cultivator
Martyr of spores
Registered: 09/08/08
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: WhAcKeD]
#9334155 - 11/29/08 08:21 PM (15 years, 3 months ago) |
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Fooman,
zeitgeist : addendum love this movie!! Glad someone else knows about it!!!
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Electric305
Hunter
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have a question,is it possible to get too powerful a fan for ones flow hood?
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4 ho cultivar
Transcending plains
Registered: 11/18/08
Posts: 379
Loc: Central, Oregon {represen...
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: Electric305]
#9342277 - 12/01/08 04:59 AM (15 years, 3 months ago) |
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evenif you do just get a light dimmer and turn down the power
-------------------- :Patience be thy virtue Blurring the line between reality and dreams Mr. Winkie says: "Procrastinators unite................................tommorrow!! G.Kahuna said: "Plus you get all the fun from taking a walk {and} shooting mycelium at cow droppings with a super soaker. Now beat that!"
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alkylbenzene23
Indeed
Registered: 08/16/08
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: 4 ho cultivar]
#9342354 - 12/01/08 06:01 AM (15 years, 3 months ago) |
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Quote:
4 ho cultivar said: evenif you do just get a light dimmer and turn down the power
Plunty of blowers can't be used with speed regulation.
-------------------- If you try to lick your cat while tripping, and they bite you, are you even?
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WhAcKeD
Researcher
Registered: 11/24/00
Posts: 307
Last seen: 13 years, 2 months
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: alkylbenzene23]
#9346587 - 12/01/08 07:24 PM (15 years, 3 months ago) |
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And you really shouldn't go below about 50% of the blowers rated output even if it is rated for use with a speed controller, so again, yes. And, of course, you are shooting for 100 feet per minute flow through the filtter. That is 100cfm for a 12x12 filter, 200 for a 12x24, 400 for a 24x24 and so on... I'm running a 24x30 HEPA, that's 2' x 2.5' = 5ft^2, and at 100 fpm that's 500 cfm I need, at .55" for the HEPA and .2" for the furnace filter prefilter, so thats.75" static pressure times 1.2 (to adjust for altitude) = .9" static pressure. Ergo, I need a blower that outputs 500cfm at a .9" static pressure. I ordered th
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WhAcKeD
Researcher
Registered: 11/24/00
Posts: 307
Last seen: 13 years, 2 months
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: alkylbenzene23]
#9346607 - 12/01/08 07:27 PM (15 years, 3 months ago) |
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Yes, you can certainly have too big a blower. You really shouldn't go below about 50% of the blowers rated output even if it is rated for use with a speed controller. And, of course, you are shooting for 100 feet per minute flow from the hood. That equals 100cfm for a 12x12 filter, 200 for a 12x24, 400 for a 24x24 and so on...
I'm running a 24x30 HEPA, that's 2' x 2.5' = 5ft^2, and at 100 fpm that's 500 cfm I need, at .55" for the HEPA and .2" for the furnace filter prefilter, so thats.75" static pressure times 1.2 (to adjust for altitude) = .9" static pressure. Ergo, I need a blower that outputs 500cfm at a .9" static pressure.
I ordered the 10" Valueline. I expect it to output around 450cfm in my application, which is a little low, but reasonably close. It is rated at a max 780cfm at 0" 70F and 0', btw, so as one can sea static pressure makes a big difference. Plans and pics coming soon... :-)
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Electric305
Hunter
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: WhAcKeD]
#9350185 - 12/02/08 09:43 AM (15 years, 3 months ago) |
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WhAcKeD,thanks so much for that explanation of the formula,i didnt get it till u explained it like that,your getting a 5 shroom rating from me for that one:-) thank you thank you
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WhAcKeD
Researcher
Registered: 11/24/00
Posts: 307
Last seen: 13 years, 2 months
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Re: Need a Cheap HEPA FIlter for Flowhood [Re: Electric305]
#9396991 - 12/09/08 12:52 AM (15 years, 3 months ago) |
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No problem Electric. So the blower's here, HEPA's are here, and I'm going to Hawaii. Talk to ya'll in a month, lol. I'll post pics of the HEPA construction, I have a couple of really neat designs to share. btw, in case anyone is interested, there doesn't seem to exist any data for the VL blowers (made by Custom Automated Products) so I looked at the data for other centrifugal blowers of similar size and made two conclusions: (1) cfm decreases from max similarly for same-diameter blowers and (2) larger diameter blowers handle static pressure better, that is rolloff is shallower. ok, goodnight.
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