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norml840
sex toy guru



Registered: 10/19/07
Posts: 3,170
Loc: lost
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Flowhood blower size
#27607900 - 01/05/22 11:02 AM (2 years, 4 months ago) |
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Man, my brain is tied in a knot trying to figure out which blower to buy. The filter I purchased says it’s designed for “a negative air machine with 125 FPM @ 1.0 in w.g. So I go to Graingers website and all of their blowers only show specs up to .8 SP.
So I bought a 24”x24”x6” Hepa Filter. Does anyone want to help an old dumb electrician figure out which blower to buy. Good grief!!
Edited by norml840 (01/05/22 03:11 PM)
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JustAPerson
Stranger


Registered: 01/23/21
Posts: 22
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Re: Flowhood blower size [Re: norml840]
#27608750 - 01/06/22 07:21 AM (2 years, 4 months ago) |
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A Dayton 1TDT8 should be fine
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micelio
Song of Silence


Registered: 04/22/14
Posts: 1,547
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WG means water gauge. SP. Is static pressure.
Think of a water gauge as a U shape glass tube that has water in it.
One end mounted in the plenum and the other end to the outside where you can view.
When you turn the flow hood on and air pressure rises in the plenum the water in the tube will rise. There a scale in inches so you can register the pressure by how high the water has risen.
Static pressure is the same as water gauge pressure. It just two ways to say the same thing...
So in short WG is how they rate filters and SP is how they rate blowers...
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micelio
Song of Silence


Registered: 04/22/14
Posts: 1,547
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Re: Flowhood blower size [Re: micelio] 2
#27608798 - 01/06/22 08:23 AM (2 years, 4 months ago) |
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I'm going to give you some good advice..
Don't take the advice of just anyone. there's a member here, His name is sandman. You can private message him for blower advice. Or he probably drop in on this thread.
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norml840
sex toy guru



Registered: 10/19/07
Posts: 3,170
Loc: lost
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Re: Flowhood blower size [Re: micelio]
#27609006 - 01/06/22 11:12 AM (2 years, 4 months ago) |
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Quote:
micelio said: I'm going to give you some good advice..
Don't take the advice of just anyone. there's a member here, His name is sandman. You can private message him for blower advice. Or he probably drop in on this thread.
Haha. I see what you did there. I’ll give it a few days to see if he drops in here. I’ll PM him if I haven’t heard anything.
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Regis
Haben wir noch pepps?

Registered: 06/07/20
Posts: 273
Loc: Germany
Last seen: 1 month, 8 days
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Re: Flowhood blower size [Re: micelio]
#27609983 - 01/07/22 04:33 AM (2 years, 4 months ago) |
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what a plottwist, the way you wrote this, i thought it would end in something like: "there's a member called sandman, fuck this guy, he doesn't know his shit"
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laughingdog
Stranger

Registered: 03/14/04
Posts: 4,830
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Re: Flowhood blower size [Re: Regis]
#27629097 - 01/22/22 11:37 PM (2 years, 3 months ago) |
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"mycology" is more & more out in the open so the info explaining in detail is even on utube:
a couple screen shots from the videos

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sandman420
Saint PP



Registered: 06/17/04
Posts: 5,384
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Re: Flowhood blower size [Re: norml840]
#27703225 - 03/21/22 08:35 AM (2 years, 1 month ago) |
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Hey! Dear sir or madam, you have besmirched me...
Did you still need any help with the blower selection?
The general idea is that static pressure is relative to the airspeed, starting at 0 (inches w.g. or what have you) with 0 air flowing.
90 fpm should be your target air speed. So if you know the test/design speed:pressure you can do a ratio calculation for your target.
125:1::90:x would be the ratio you want to figure. That works out to be x=0.72. This is a pretty good high pressure filter what brand is it?
Alright then so you want around 325 cfm @ 0.72" static pressure to make 90 fpm out of the filter (considering frame size removed from filter face)
add the prefilter 0.2" is standard but they actually add between 0.1"-0.2" depending on brand and type and speed you run them at.
Furnace filters are designed to run 300 fpm so size it appropriately.
So you want a blower that makes at least 325 cfm @ ~0.8-0.9". Don't go dummy big because they don't like to make under a certain airflow and vibrate and make uneven air. You can go somewhat bigger and choke some of the intake and remove it as the filter loads up to get more service life but this isn't such a big deal. 2 years vs 3 years continuous maybe.
Pro hoods use speed controlled "special" blowers to achieve these changes but dayton blowers don't play nice with speed controllers all the time and not recommended.
Edited by sandman420 (03/21/22 08:40 AM)
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