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starbones
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Can I borrow someone with a functional brain for flowhood math?
#26607935 - 04/17/20 11:25 AM (3 years, 9 months ago) |
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I know this is most likely the most annoying question you all get asked but I'm hilariously and I mean hilariously bad at anything beyond simple math due to a combination of ADHD and medication for TN.
The filter I have has a face measurement of around 16x16 which I know is small but you gotta dance with the dick what brought you. It's got some ratings. 750 m3/h Norminal airflow. (So like, 441 CFM I think) Pressure drop is 219 +/- 15% Pa (Which I think is around .88 in wg) 99.99% on 0.3micron.
I don't need to know which fan exactly to buy just what I need it to supply. Thank you. I am hopefully going to buy a TD-Silent fan from Soler and Palau which are mixed flow axial fans and their smallest can do 200ish CFM at 0.5 in wg. Hoping to have something quiet so I can use it as a home air purifier as well.
I'm sorry I'm stupid and I understand these constant posts get annoying.
-------------------- Listen, I'm steel fisted with the iron lung Heavy metal ballads out the guitar where lions run.
 
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starbones
I'm an alien, I eat uranium.



Registered: 03/04/20
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Re: Can I borrow someone with a functional brain for flowhood math? [Re: starbones]
#26608159 - 04/17/20 01:27 PM (3 years, 9 months ago) |
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The way I understand it is I have 16x16" so 1.3x1.3' or 1.7 ft So to have 100cfm through the filter I require 170 cfm. If the static resistance is .88 wg then I need a blower capable of 170cfm at .88wg.
Maybe?
-------------------- Listen, I'm steel fisted with the iron lung Heavy metal ballads out the guitar where lions run.
 
Edited by starbones (04/17/20 01:28 PM)
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oldest hippie
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Re: Can I borrow someone with a functional brain for flowhood math? [Re: starbones]
#26608208 - 04/17/20 01:50 PM (3 years, 9 months ago) |
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Quote:
starbones said: The way I understand it is I have 16x16" so 1.3x1.3' or 1.7 ft So to have 100cfm through the filter I require 170 cfm. If the static resistance is .88 wg then I need a blower capable of 170cfm at .88wg.
Maybe?
You are on the right track. The filter has a curve just like the the fan does. You know the resistance of the filter at 441cfm , but what is the resistance at 170cfm? It maybe different and the fan should be capable of supplying 170cfm at that resistance.
-------------------- Time gets much more valuable the older I get, and no matter how much money I spend, I can't get a second of it back.
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starbones
I'm an alien, I eat uranium.



Registered: 03/04/20
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Re: Can I borrow someone with a functional brain for flowhood math? [Re: oldest hippie]
#26608262 - 04/17/20 02:14 PM (3 years, 9 months ago) |
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And I can't find the filter on Camfil's website sadly to find that chart.

It's weird to me it's rated H13 but then also says 99.99%@0.3um Not sure what the 99.95 rating is above it. MP something. If these end up being no good for mycology work that's no stress I got two of them for $50 for the pair and could use some cleaner air in my home. Oh the 99.95% is the Most Penetrating Particle Size keeps out 99.99% of 0.3 and larger though so that's swell.
Edited by starbones (04/17/20 02:22 PM)
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bodhisatta 
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Re: Can I borrow someone with a functional brain for flowhood math? [Re: starbones]
#26608321 - 04/17/20 02:42 PM (3 years, 9 months ago) |
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Stop thinking of it as math. It's just comparing numbers.
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starbones
I'm an alien, I eat uranium.



Registered: 03/04/20
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Re: Can I borrow someone with a functional brain for flowhood math? [Re: bodhisatta]
#26608342 - 04/17/20 02:54 PM (3 years, 9 months ago) |
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I am bad at that too bod. I will never claim to be a clever man and with my current medications I am on par intellectually with a coir brick.
This is why I use your teks because I could try to wrap my head around convection currents for FAE but my brain is more hardwired to understand things like "put grocery bag on shoebox and leave it alone"
I e-mailed Camfil to see if I can get that chart for wg/cfm so I guess I am stuck until then. Hopefully this filter doesn't require a blower that sounds like Satans asshole.
-------------------- Listen, I'm steel fisted with the iron lung Heavy metal ballads out the guitar where lions run.
 
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starbones
I'm an alien, I eat uranium.



Registered: 03/04/20
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Re: Can I borrow someone with a functional brain for flowhood math? [Re: bodhisatta]
#26608541 - 04/17/20 04:33 PM (3 years, 9 months ago) |
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Quote:
bodhisatta said: Stop thinking of it as math. It's just comparing numbers.
Since the filter has a wg of 0.88 at 441cfm on the sticker could I just use a blower with rated to 200cfm (slightly above what I need for 100 out the front) at 1" wg? That way I know I have more than enough blower for what I need or would that cock things up flow wise out the front?
-------------------- Listen, I'm steel fisted with the iron lung Heavy metal ballads out the guitar where lions run.
 
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starbones
I'm an alien, I eat uranium.



Registered: 03/04/20
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Re: Can I borrow someone with a functional brain for flowhood math? [Re: starbones]
#26617078 - 04/21/20 08:29 AM (3 years, 9 months ago) |
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Hey bod, so this is what they sent.

Calculations put my flow rate around 170cfm for what I need. If I bump that to 200-215 which would be ~339 m3h on that chart that requires 0.4 in wg
That doesn't seem like enough for laminar flow so I guess I'm building an air purifier, haha.
Close enough?
Edited by starbones (04/21/20 08:32 AM)
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starbones
I'm an alien, I eat uranium.



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Re: Can I borrow someone with a functional brain for flowhood math? [Re: starbones]
#26617110 - 04/21/20 08:46 AM (3 years, 9 months ago) |
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Then judging by this spec chart. I should be good with this blower if I add 0.2wg with a pre-filter to choke it up. Should put me around 200-210 cfm.
If I'm off the mark lemme know!
-------------------- Listen, I'm steel fisted with the iron lung Heavy metal ballads out the guitar where lions run.
 
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oldest hippie
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Re: Can I borrow someone with a functional brain for flowhood math? [Re: starbones]
#26617626 - 04/21/20 12:12 PM (3 years, 9 months ago) |
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Quote:
starbones said: Then judging by this spec chart. I should be good with this blower if I add 0.2wg with a pre-filter to choke it up. Should put me around 200-210 cfm.
If I'm off the mark lemme know!

You may find that you have too much air flow. You could also restrict the amount of air at the suction of the blower by using a sort of damper. Something that you can adjust. With the added pre-filter, and an inlet damper, it should work.
-------------------- Time gets much more valuable the older I get, and no matter how much money I spend, I can't get a second of it back.
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oldest hippie
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Re: Can I borrow someone with a functional brain for flowhood math? [Re: starbones]
#26620146 - 04/22/20 02:23 PM (3 years, 9 months ago) |
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The air mover that you picked out is an axial flow fan, so the air exiting from the fan spirals and so is not laminar flow. You could put baffles in the plenum to straighten the flow, or you could choose a blower that puts out linear flow. A centrifugal blower straightens the flow in the discharge volute. The filter resistance has nothing to do with whether the flow is laminar or not. The 1"wg that you mention is a typical resistance of an 11" deep filter, at least to my knowledge. As I recall, the Reynolds number is a measure of the relative roughness of the inside of the pipe or duct. You can safely ignore it. The static pressure is the maximum pressure that the fan can produce with the discharge shut off. The 100 cfm flow rate is supposed to be able to bend the flame of a candle without blowing it out, and allows you to be able to work in clean air without disturbing the surrounding air.
-------------------- Time gets much more valuable the older I get, and no matter how much money I spend, I can't get a second of it back.
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starbones
I'm an alien, I eat uranium.



Registered: 03/04/20
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Re: Can I borrow someone with a functional brain for flowhood math? [Re: oldest hippie]
#26620194 - 04/22/20 02:51 PM (3 years, 9 months ago) |
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Negatory, that Dayton unit is a centrifugal squirrel cage fan. The Soler and Palau was earlier on in the thread.
Axial flow fans are fine as no air mover I've seen in any unit anyone has built is shooting directly at the filter. It's filling a plenum first. There's a few folks on here who have non-squirrel cage in-line fans and they're doing just fine. Thanks though, appreciate it.
You're also off base on the in wg and 11" thing too, don't know where that idea is coming from as plenty of 4-6" filters have 1" wg and plenty of thicker ones have less, it's filter specific. I think you have a few things confused in general, not meaning to offend but misinformation grows like trichoderma.
-------------------- Listen, I'm steel fisted with the iron lung Heavy metal ballads out the guitar where lions run.
 
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oldest hippie
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Re: Can I borrow someone with a functional brain for flowhood math? [Re: starbones]
#26620284 - 04/22/20 03:26 PM (3 years, 9 months ago) |
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Ok. Thank you.
-------------------- Time gets much more valuable the older I get, and no matter how much money I spend, I can't get a second of it back.
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