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contaman
journeyman
Registered: 05/27/02
Posts: 53
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Flowhood question
#674624 - 06/12/02 09:19 AM (21 years, 3 months ago) |
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Okay.
Say that some crazy elf was dedicated enough that he decided he would try to build This Flowhood (thanks phrozendata for the link!)
After it is completed, what would be the recommended way to use it?
I understand that it sucks in air and replaces it with HEPA filtered air, but should it still be used in addition to a glove box? I mean, will it be powerful enough to clean an entire rooms summer time, spore laden air? Can it just sit on a clean table with work being done in front? Am i totally missing something?
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DinoMyc
Ipsa scientiapotestas est
Registered: 11/13/99
Posts: 1,080
Last seen: 17 years, 3 months
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Re: Flowhood question [Re: contaman]
#674870 - 06/12/02 12:16 PM (21 years, 3 months ago) |
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glove boxes are old hat, however a hood over the workspace is a good idea with a hepa not in a clean environment. TMC and GGMM have calculations and reccomendations for applications of hepa filters. work is"just done in front", however everything must be clean within that area, else it is no longer clean (the area downstream from the dirty piece of equipment)..
-------------------- If I made affront, I apologize. If I made affirmation, I apologize. I merely came to listen, came to say.
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ggordon
Stranger
Registered: 06/17/02
Posts: 17
Last seen: 18 years, 11 days
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Re: Flowhood question [Re: contaman]
#687884 - 06/19/02 08:01 AM (21 years, 3 months ago) |
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The idea behind a flow hood is that it creates a positive pressure where you are working. So if you clean the area first and have a flow of clean air across the work surface where can your contams come from? I am building one as we speak but only working with edibles.
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Macey Howard
Formally MOE HOWARD


Registered: 07/02/99
Posts: 14,165
Loc: Georgia
Last seen: 7 years, 1 month
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Post deleted by Moe Howard [Re: ggordon]
#688468 - 06/19/02 02:22 PM (21 years, 3 months ago) |
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-------------------- Hugs and Kisses!
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ggordon
Stranger
Registered: 06/17/02
Posts: 17
Last seen: 18 years, 11 days
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I'll post some pics and some basic plans when I'm done. I have alot of stuff to do right now so expect a delay of about 3 weeks or so. I am also in the process of putting a control system together to control temp, CO2, humidity lights, the whole shabang. Will be done with a BasicX 24 microcontroller so I will post the code and a schematic when done. Like I said though, busier than shit right now.
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Anonymous
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Post deleted by Moe Howard [Re: Macey Howard]
#688525 - 06/19/02 02:51 PM (21 years, 3 months ago) |
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Anonymous
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Post deleted by Moe Howard [Re: ]
#688529 - 06/19/02 02:54 PM (21 years, 3 months ago) |
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nw2shroom
shroom deity
Registered: 02/18/02
Posts: 229
Loc: Tu hablas el Spanglish??
Last seen: 16 years, 4 months
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Re: Flowhood question [Re: ]
#688786 - 06/19/02 05:10 PM (21 years, 3 months ago) |
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hey look in my post history at least 3 months back or so , i posted my flowhhod/hepa box, use the pics for ideas, you might want to make it smaller than mine though,, under 60 bucks,,,
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aural
Hola Amigos!
Registered: 05/03/00
Posts: 511
Loc: The Desert In The Spring
Last seen: 19 years, 6 months
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Re: Flowhood question [Re: contaman]
#689604 - 06/20/02 03:23 AM (21 years, 3 months ago) |
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contaman- You don't need a glovebox if you have a flowhood. It doesn't really matter how clean the air in the entire room is.The point is that when you have a flow of sterile air to work under,contams will be blown out of that area.
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Anno
Experimenter



Registered: 06/17/99
Posts: 24,162
Loc: my room
Last seen: 3 days, 10 hours
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Re: Flowhood question [Re: contaman]
#689810 - 06/20/02 05:42 AM (21 years, 3 months ago) |
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>I understand that it sucks in air and replaces it with HEPA >filtered air, but should it still be used in addition to a glove >box? No, only the hood.
> I mean, will it be powerful enough to clean an entire rooms summer time, spore laden air? Yes.
>Can it just sit on a clean table with work being done in front? Exactly, that?s the way how it?s done.
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ggordon
Stranger
Registered: 06/17/02
Posts: 17
Last seen: 18 years, 11 days
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Re: Flowhood question [Re: Anno]
#690038 - 06/20/02 08:05 AM (21 years, 3 months ago) |
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I am talking flow hood. I guess by saying "positive pressure" it is kind od misleading because as soon as the air gets sucked through the filters and pushed out across the work space it is at atmospheric pressure. Perhaps saying a positive velocity would have been better. Glove boxes are just a hassle. I build one years ago and had nothing but problems. Mind you, I have seen this one design out there which uses a computer cooling fan to create your "positive pressure" Looks good and cheap to build. The only real expense you will have is your hepa filter if you can build everything else. The one question I would like to ask is if anyone has the formula for calculating your CFM air flow for optimum results based on the size of the hepa filter (the surface area of the outlet)
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Anno
Experimenter



Registered: 06/17/99
Posts: 24,162
Loc: my room
Last seen: 3 days, 10 hours
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Re: Flowhood question [Re: ggordon]
#690332 - 06/20/02 10:58 AM (21 years, 3 months ago) |
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A big expense is also the blower.
>The one question I would like to ask is if anyone has the >formula for calculating your CFM air flow for optimum results >based on the size of the hepa filter (the surface area of the >outlet)
Stamets says the air esape velocity from the hepa filter should be 100 feet per minute. So, if you have a filter 2x1 feet, you will need a blower that delivers 200 cubic feet per minute at a statical pressure of 1.3 inch water level(1 inch for the HEPA and 0.3 inch for the prefilter).
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ggordon
Stranger
Registered: 06/17/02
Posts: 17
Last seen: 18 years, 11 days
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Re: Flowhood question [Re: Anno]
#691484 - 06/20/02 07:36 PM (21 years, 3 months ago) |
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Thanks Anno. It figures that it was in "The" book eh.
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