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Groo
sola dosis facit venenum



Registered: 12/06/14
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36x72 laminar flow hood
#27052602 - 11/22/20 05:17 PM (3 years, 2 months ago) |
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Good evening friends. And I found myself with more luck then I know what to do with. I have got a hold of a 36 by 72 (for $200) and I've done the math it seems like I need 1600 cfm I've been looking at the dayton blowers and it seems like they've maxed out 900 or 1000 cfm if I stick two 800 cfm blowers on it will provide me my desired effect or can somebody suggest a blower fan that's of the appropriate size?

Aerostar 22388B 6 inch
here are the specs
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bodhisatta 
Smurf real estate agent


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Re: 36x72 laminar flow hood [Re: Groo]
#27052668 - 11/22/20 05:44 PM (3 years, 2 months ago) |
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Probably looking at 240v blowers
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natedawgnow
Rocky mountain hood rat



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Re: 36x72 laminar flow hood [Re: bodhisatta]
#27052809 - 11/22/20 07:06 PM (3 years, 2 months ago) |
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For a hood that size I'd go with an old furnace blower for like a 2000sqft house.
One that's nearly 1hp. Should be plenty big and may even need to be dialed down a tad. A standard furnace blower for a 3 ton system at open air is a bit under 1500cfm
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Groo
sola dosis facit venenum



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I'm finding those aren't rated in CFM could you tell me the trick to figure out the CFM of a fan has one that's not on the thing usually it's for specific air handler units and I'm having a hard time getting specs cuz I'm not in front of a real computer yet here's what I found so far that seems like it would maybe work and thanks to everyone for taking a moment to read over and leave some comments is this too big will know s*** obviously it's way too big I planned on getting originally a 24 by 12 and then I figured a little taller so 24 by 18 and I was like oh it's not that bad to go get up 36 by 17 or 18 and then I found this one I can't believe the guy accepted two hundred bucks for it if there's a serious Mycologist out there who would like to buy it well under half price of brand new let me know with a p.m. I really don't need one this damn big but
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Groo
sola dosis facit venenum



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Re: 36x72 laminar flow hood [Re: Groo]
#27052887 - 11/22/20 08:04 PM (3 years, 2 months ago) |
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Also I would really really like to run this baby off of 110 so I don't have to make a circuit combiner from two separate circuits or putting the lab closer to 220v
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Groo
sola dosis facit venenum



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Re: 36x72 laminar flow hood [Re: Groo]
#27052890 - 11/22/20 08:05 PM (3 years, 2 months ago) |
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Also if somebody knows more about fluid dynamics would putting two 800 CFM blowers together in the same flow Hood produce 1600 CFM
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natedawgnow
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Re: 36x72 laminar flow hood [Re: Groo] 1
#27053016 - 11/22/20 09:30 PM (3 years, 2 months ago) |
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You wont find a furnace blower like Im talking about on google.
Call some hvac companies and ask if they have any old furnace blowers for a 4 ton system lying around and they may be willing to give you one for free.
As for the fluid dynamic question, as far as I know, no 2x 800cfm blowers together will not produce 1600cfm. Flow rate of different combined streams is an average of the velocity of both streams upon combining.
So 2 streams, each at a cfm of 800 combine to form a stream that moves at an average of both velocities, which is also 800cfm. At least this is how it works if the 2 fans are wired in parallel. Pressure will increase but flow rate wont.
Imagine 2 streams of water moving parallel to eachother at the same speed. If they come together at some point, they will continue to flow at the speed each stream was originally flowing at. They cant just magically pick up speed, energy, without some outside force to increase it.
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Groo
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I am not so sure that what you're saying is true. what's a we have 1 flow of water going down a 4-inch Channel now if you take two of those flows and then combine them into one channel that's exactly the same size you have twice the volume of water and it displaces itself I think moving faster but if you have one water moving down one channel and then you go behind it slightly and add another water I'm pushing in the same direction on the same channel size nothing will happen but if you converge two waters and two a smaller Channel I think the speed will double. In fact I think I may be correct a few minutes worth of research and here's my source see this article is here so yes series and parallel of fans in a system are actually a thing://www.achrnews.com/articles/106299-multiple-fan-systems-fans-in-series-and-parallel
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Groo
sola dosis facit venenum



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Re: 36x72 laminar flow hood [Re: Groo]
#27053190 - 11/22/20 10:27 PM (3 years, 2 months ago) |
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See here it looks like two fans would work if put together the right way
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
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Quote:
natedawgnow said: You wont find a furnace blower like Im talking about on google.
Call some hvac companies and ask if they have any old furnace blowers for a 4 ton system lying around and they may be willing to give you one for free.
As for the fluid dynamic question, as far as I know, no 2x 800cfm blowers together will not produce 1600cfm. Flow rate of different combined streams is an average of the velocity of both streams upon combining.
So 2 streams, each at a cfm of 800 combine to form a stream that moves at an average of both velocities, which is also 800cfm. At least this is how it works if the 2 fans are wired in parallel. Pressure will increase but flow rate wont.
Imagine 2 streams of water moving parallel to eachother at the same speed. If they come together at some point, they will continue to flow at the speed each stream was originally flowing at. They cant just magically pick up speed, energy, without some outside force to increase it.
Cfm is a measure of volume not speed. To parallel streams of 800cfm make a flow of 1600cfm. If there's not too much back pressure that is.
Think of cfm as a gallon. Two streams of 800 gallons per minute make a total of 1600 gallons per minute unless they get backed up.
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RoscoeReturns
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Re: 36x72 laminar flow hood [Re: bodhisatta]
#27053403 - 11/23/20 05:42 AM (3 years, 2 months ago) |
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Two blowers together would absolutely work. Some commercial laminar flow hoods use two smaller blower instead of one large blower.
That carpet dryer fan you posted will Not work. Those will move a lot of air, but not with much back pressure. CFM is only part of the equation when picking a fan. Your filter is rated 0.64” wg@2250CFM. You don’t need to flow quite so much air, 3’ x 6’ = 18sq ft x 100fpm = 1800cfm. Look for a blower that can push 1800-2000cfm@0.6”wg. Don’t buy anything if you can’t find the pressure AND flow rating for. 1800cfm with no back pressure will not work when you put it behind your filter. If you do decide on two blowers you can half the cfm for each, but not the pressure. So look for two fans rated for 1000cfm@0.6”wg, or something close to that.
Edited by RoscoeReturns (11/23/20 06:12 AM)
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natedawgnow
Rocky mountain hood rat



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Re: 36x72 laminar flow hood [Re: bodhisatta]
#27053592 - 11/23/20 08:48 AM (3 years, 2 months ago) |
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Quote:
bodhisatta said:
Quote:
natedawgnow said: You wont find a furnace blower like Im talking about on google.
Call some hvac companies and ask if they have any old furnace blowers for a 4 ton system lying around and they may be willing to give you one for free.
As for the fluid dynamic question, as far as I know, no 2x 800cfm blowers together will not produce 1600cfm. Flow rate of different combined streams is an average of the velocity of both streams upon combining.
So 2 streams, each at a cfm of 800 combine to form a stream that moves at an average of both velocities, which is also 800cfm. At least this is how it works if the 2 fans are wired in parallel. Pressure will increase but flow rate wont.
Imagine 2 streams of water moving parallel to eachother at the same speed. If they come together at some point, they will continue to flow at the speed each stream was originally flowing at. They cant just magically pick up speed, energy, without some outside force to increase it.
Cfm is a measure of volume not speed. To parallel streams of 800cfm make a flow of 1600cfm. If there's not too much back pressure that is.
Think of cfm as a gallon. Two streams of 800 gallons per minute make a total of 1600 gallons per minute unless they get backed up.
Yes your example makes sense in my mind, but it depends on whether or not the fans are in parallel or series which I was attempting to convey but it looks like I got it backwards in my explanation
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
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Its hard to put blowers in series for something like a flow hood, unless they're inline in a tube or something. Otherwise they're technically parallel if both blowing into the plenum
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Groo
sola dosis facit venenum



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Re: 36x72 laminar flow hood [Re: bodhisatta]
#27054783 - 11/23/20 11:37 PM (3 years, 2 months ago) |
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We cannot say that the blue fan would not work without checking the manufacturer specs to see what how many columns of water this biznitch can pump 1600 CFMsthrough live fairly certain that's what's 0 resistance would it produce a laminar stream leaving the filter certainly would it be 100 CFM probably nowhere near yeah my AC guy told me not to worry and that he has a million billion gazillion fans that are variable speed and can go slightly over 1600 CFM or slightly lower depending on out put measured 1 systems together
Edited by Groo (11/23/20 11:38 PM)
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