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ravin0ff
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Registered: 10/03/04
Posts: 227
Last seen: 9 years, 3 months
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contams at 99.97% effecient filter? need posi pressure glovebox expert...
#3625478 - 01/13/05 08:39 PM (19 years, 2 months ago) |
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Has anyone made a positive pressure glovebox with a 99.97% .3 micron hepa filter and got contams from working in it? (are you POSITIVE you recieved the contam from the air, and not through faulty steralization processes?)
does this filter look okay to everyone? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=43530&item=4340833530&tc=photo
Stamets suggests that 100 fpm is optimal for flowhoods, but the required airflow in positive pressure gloveboxes must be based on the size of glovebox. Can anyone give me any information regarding this?
Thank you for all help and information
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onetime
onetime
Registered: 11/13/03
Posts: 3,609
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Re: contams at 99.97% effecient filter? need posi pressure glovebox expert... [Re: ravin0ff]
#3625515 - 01/13/05 08:46 PM (19 years, 2 months ago) |
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http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26237&item=3866863411&rd=1
try to get one of these there is always 5 of them and just make a flow hood they cost about the same to build or maby 25$ more
or this one http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26415&item=3867057629&rd=1
this was was 1$ then the bid ended and comcast shut down now it looks like poeple want it
-------------------- See? Yes, with my own three eyes. Depression, Misspells , wanting everying thing i cant have haveing nothing i want
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dog
straw dog
Registered: 06/20/02
Posts: 2,790
Loc: Route 66
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Re: contams at 99.97% effecient filter? need posi pressure glovebox expert... [Re: ravin0ff]
#3625548 - 01/13/05 08:50 PM (19 years, 2 months ago) |
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I'm hardly an expert but I did build my own positive pressure glove box. The only time I encountered airborne contamination was when I set the airflow too low. I think the low pressure caused a "backwash" of unfiltered room air to blow back in through the armholes. As long as I keep the pressure up (a pretty good breeze) I'm virtually contam free.
-------------------- Fascism (fash'izem) n. A governmental system marked by a centralized dictatorship, stringent socioeconomic controls, and often belligerent nationalism. see also: the Bush Administration.
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ravin0ff
Stranger
Registered: 10/03/04
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Re: contams at 99.97% effecient filter? need posi pressure glovebox expert... [Re: dog]
#3625651 - 01/13/05 09:09 PM (19 years, 2 months ago) |
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thanks for the suggestion, but I've decided on positive pressure glovebox, it is cheaper, lightweight, and does the same thing. dog, what do you use to provide pressure, fan or hepa machine?
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LaughingJim
Anti-Toxin
Registered: 09/30/04
Posts: 465
Loc: USA, ( CT )
Last seen: 18 years, 6 months
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Re: contams at 99.97% effecient filter? need posi pressure glovebox expert... [Re: ravin0ff]
#3625723 - 01/13/05 09:25 PM (19 years, 2 months ago) |
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One thing you may notice on some cheap filters that "Claim" 99.97% is that the actual FILTER is rated at that, not the filter houseing.
If the filter is not glued directly to the frame of the housing, eg home central air filters... then you will have 100% contamination. Air will blow between the filter and the cheap card-board housing.
All true hepa filters have solid housing of plastic, or metal. They are glued/bonded directly to the housing. They have some form of gasket attached to the housing, or they expect that one is attached to the hood.
Central air filters only claim that the filter material is 99.98%, which it is... any air that doesn't leak out the sides, and actually passes through the filter will be filtered at 99.98%. At high pressure, that is about 75%-85% of the passing air. At low pressure, that is only about 25%-50% of the air, since the gaps will allow more air through, faster than the filter will.
-------------------- Don't forget to RATE us if you think we are offering GOOD or BAD advice, Thank-you! I participate in the PROTEIN FOLDING PROGRAM helping the shroomery to help others, FOLDING.STANFORD.EDU I support www.shroomery.org (Team # 12679)
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LaughingJim
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Re: contams at 99.97% effecient filter? need posi pressure glovebox expert... [Re: LaughingJim]
#3625731 - 01/13/05 09:27 PM (19 years, 2 months ago) |
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That is a vacume filter... you NEED a lot of pressure to push through that, not suction... Like 20 PSI (12 amps vacume) Go to any store that sells air filters and pick up a 99.98% filter for $15.00 (Holmes rectangular single room filter.) $11.00 if you buy them in twos!
-------------------- Don't forget to RATE us if you think we are offering GOOD or BAD advice, Thank-you! I participate in the PROTEIN FOLDING PROGRAM helping the shroomery to help others, FOLDING.STANFORD.EDU I support www.shroomery.org (Team # 12679)
Edited by LaughingJim (01/13/05 09:29 PM)
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dog
straw dog
Registered: 06/20/02
Posts: 2,790
Loc: Route 66
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Re: contams at 99.97% effecient filter? need posi pressure glovebox expert... [Re: ravin0ff]
#3627082 - 01/14/05 02:33 AM (19 years, 2 months ago) |
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Quote:
dog, what do you use to provide pressure, fan or hepa machine?
It is a hepa machine. I mounted a 4" dryer hose to the exhaust and ran it to my glove box, which is a large stearlite bin with arm holes and a piece of plexiglass mounted into the lid. She's not very pretty but she works like a charm.
-------------------- Fascism (fash'izem) n. A governmental system marked by a centralized dictatorship, stringent socioeconomic controls, and often belligerent nationalism. see also: the Bush Administration.
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Flashman
Sir
Registered: 01/05/05
Posts: 38
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Last seen: 19 years, 26 days
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Re: contams at 99.97% effecient filter? need posi pressure glovebox expert... [Re: dog]
#3627400 - 01/14/05 04:42 AM (19 years, 2 months ago) |
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Dog, I have got one of these
http://www.shroomery.org/forums/showflat.php/Cat/0/Number/3616848/an/0/page/8
To make a Hood from it, I'd need to glue / fix air hoses from its four outlets to the glove box.
I thought this may not work as air is drawn through the HEPA, through the Motor, then would go through the air hoses to the Hood.
The Hood designs I'd read involved the HEPA filter being present in the Hood, so that it can be sprayed with lysol / bleach etc before use.
What about contamination risks from the moror, motor housing or air hoses after the HEPA?
Do people think adding air - hoses to the Defender will be suitable to create a hood?!?
Hope so
-------------------- Woof Woof
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ravin0ff
Stranger
Registered: 10/03/04
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Last seen: 9 years, 3 months
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Re: contams at 99.97% effecient filter? need posi pressure glovebox expert... [Re: Flashman]
#3631048 - 01/15/05 12:20 PM (19 years, 2 months ago) |
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Laughjim, lets say the crappily bonded filter is 5 inches by 7 inches, Can I just make a hole 3 inches in diameter on the side of my glovebox, and attach it so the hole is in the center?
also, can a computer fan every hope to achieve 20 psi?
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Flashman
Sir
Registered: 01/05/05
Posts: 38
Loc: Location, Loction
Last seen: 19 years, 26 days
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Re: contams at 99.97% effecient filter? need posi pressure glovebox expert... [Re: ravin0ff]
#3631055 - 01/15/05 12:21 PM (19 years, 2 months ago) |
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"can a computer fan ever hope to achieve 20 psi? "
no
-------------------- Woof Woof
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