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pandelic
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Flowhood HEPA filter
#26858618 - 08/02/20 11:01 AM (3 years, 5 months ago) |
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Hello, I am on the process of starting a new Flowhood. Having a hard time finding a 24x24 HEPA filter for the new hood. I have an ac blower already with a rheostat to control the flow as the blower will overpower most filters.
Anyone recommend a place to order from?
I have seen many places the sell but I'm not getting a warm feeling about any of them. This is the one i thought of purchasing as the best fit https://www.ebay.com/itm/American-AirFilter-550-205-005-24-x-24-x-11-5-Astrocel-HEPA-Air-Filter/363025259451?epid=24008414992&hash=item5485fddbbb:g:G0wAAOSwozpe670q:sc:UPSGround!33185!US!-1
Hope someone can change my mind. Thanks
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sandman420
Saint PP



Registered: 06/17/04
Posts: 5,384
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Re: Flowhood HEPA filter [Re: pandelic]
#26858740 - 08/02/20 11:57 AM (3 years, 5 months ago) |
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It would be pretty hard to beat that price. I'd prefer a 6" filter over a 12" filter personally but many people use them. 6" filter has around twice the resistance/SP as a 12" filter, and higher SP makes for better laminar flow.
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pandelic
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Re: Flowhood HEPA filter [Re: sandman420]
#26858821 - 08/02/20 12:46 PM (3 years, 5 months ago) |
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Quote:
sandman420 said: It would be pretty hard to beat that price. I'd prefer a 6" filter over a 12" filter personally but many people use them. 6" filter has around twice the resistance/SP as a 12" filter, and higher SP makes for better laminar flow.
to be honest I'm not trying to beat the price as much as get something from a reliable source.
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sandman420
Saint PP



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Posts: 5,384
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Re: Flowhood HEPA filter [Re: pandelic]
#26859141 - 08/02/20 03:18 PM (3 years, 5 months ago) |
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Edited by sandman420 (08/02/20 03:20 PM)
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pandelic
Wild Panda



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Re: Flowhood HEPA filter [Re: sandman420]
#26859265 - 08/02/20 04:52 PM (3 years, 5 months ago) |
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Quote:
sandman420 said: https://www.ebay.com/itm/KOCH-H23G3X1-Filter-HEPA99-99-Prtcl-30x30x5-875/273916770935?hash=item3fc6b63a77:g:XXQAAOSwRmNdHvG0
30x30 is best MINIMUM size IME.
It will be a 1-2 months though they build it new to order.
interesting, My last flow hod was 12x24. lol. i think I'm good with the 24x24 size. its going in a closet compartment 26 inches wide. i do like the 99.99. do you recommend KOCH or is just the size you think fits best?
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pandelic
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Re: Flowhood HEPA filter [Re: pandelic]
#26859272 - 08/02/20 04:54 PM (3 years, 5 months ago) |
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 this was it
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sandman420
Saint PP



Registered: 06/17/04
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Re: Flowhood HEPA filter [Re: pandelic]
#26859606 - 08/02/20 07:37 PM (3 years, 5 months ago) |
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Yea the koch ones are working good, I couldn't find 24x24x5-7/8 99.99 though for some reason. If you order from zoro on there they will take care of you (not me obviously its a multimillion corp)
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senescence
Stranger

Registered: 09/02/19
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Re: Flowhood HEPA filter [Re: sandman420]
#26859624 - 08/02/20 07:54 PM (3 years, 5 months ago) |
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my hood is 24x24x12. it's so thicc after the plenum, I didn't realize they made them 6" deep at the time. That being said, I haven't been hindered by it's height even when g2g'ing into spawn bags, but often feel limited by it's width.
Quote:
sandman420 said: higher SP makes for better laminar flow.
How can laminar flow be 'better'? I was under the impression flow is either laminar or it is not.
Edited by senescence (08/02/20 07:56 PM)
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sandman420
Saint PP



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Re: Flowhood HEPA filter [Re: senescence]
#26860011 - 08/03/20 04:17 AM (3 years, 5 months ago) |
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You are right that something is either laminar or not technically. And it is my experience that homemade hoods are typically not perfectly a laminar flow. There will be some fluctuation in the airspeed across the filter from center outwards if you test with a hot wire anemometer. But with a higher SP there will be less fluctuation across the filter and thus "more laminar" and less possibility for backwashed air and Eddie currents.
In short....higher sp = easier to make close to laminar which is why 6" filter are preferable over 12" filters.
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,889
Loc: Milky way
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Re: Flowhood HEPA filter [Re: sandman420]
#26860040 - 08/03/20 05:11 AM (3 years, 5 months ago) |
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Quote:
sandman420 said: It would be pretty hard to beat that price. I'd prefer a 6" filter over a 12" filter personally but many people use them. 6" filter has around twice the resistance/SP as a 12" filter, and higher SP makes for better laminar flow.
Laminar is laminar. There's not "better laminar flow"
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sandman420
Saint PP



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Re: Flowhood HEPA filter [Re: bodhisatta]
#26860062 - 08/03/20 05:47 AM (3 years, 5 months ago) |
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Closer to laminar. If you take your hot wire anemometer and run it around the filter and find a 1 single fpm difference it is technically not laminar right? Your hood doesnt even have that level of laminar I would wager a lot of money on it.
I really didnt want to argue semantics this early in the morning.
If you really want to get right down to it stop calling your own hoods laminar then because they aint true laminar if we want to argue such semantics. You all know what I mean. Closer to an even veocity is a good thing. You want to be as even as you can.
5-10fpm velocity difference accross filter is acceptable. And technically not laminar.
My point is a higher SP creates a more even velocity across the face of the filter than a lower SP filter in the same plenum.
Lower the SP and a more larger plemum you will need to prevent excess high pressure areas blowing harder in concentrated locations.
Edited by sandman420 (08/03/20 05:59 AM)
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,889
Loc: Milky way
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Re: Flowhood HEPA filter [Re: sandman420]
#26860303 - 08/03/20 08:51 AM (3 years, 5 months ago) |
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Quote:
sandman420 said: I really didnt want to argue semantics this early in the morning.
If you really want to get right down to it stop calling your own hoods laminar then because they aint true laminar if we want to argue such semantics. You all know what I mean. Closer to an even veocity is a good thing. You want to be as even as you can.
5-10fpm velocity difference accross filter is acceptable. And technically not laminar.
Laminar has absolutely nothing to do with relative flow rates. It's only dealing with the vectors for the particles in flow all being the same direction in a given moment. In pipes with laminar flow the liquid near the walls has significantly less velocity than in the center of the flow. It's still laminar and not any less laminar than your theorized ideal situation. Laminar flow can also bend and relative velocities between particles change. All the particles directions change uniformly but the velocities do not.
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