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Phluxx
Stranger
Registered: 03/04/15
Posts: 1
Last seen: 8 years, 6 months
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Laminar Flowhood question
#21359819 - 03/04/15 07:49 AM (9 years, 2 months ago) |
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I recently built a flowhood using an h14 hepa filter with the dimensions : 305mm x 610mm x 70mm
The pre filter is a opel corsa air filter - currently mounted between the blower and hepa filter.
The blower i purchased was incorrect(read the wrong damn data sheet) it was a Kruger KDD 7/7 165W 4P-1 1SY
it seems the correct amount of airflow would be 340 cubic meters per second at 300Pa - is this correct ?
is there any chance my ex-blower could have damaged my hepa by blowing it too hard ?
a new blower is to be purchased based on the replies here - (can i link to the site that i want to buy my fan from ?)
here are some pics




here is the old blowers datasheet
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Mushroom Hill
Old Member, New Name

Registered: 03/08/15
Posts: 2
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Re: Laminar Flowhood question [Re: Phluxx]
#21377403 - 03/08/15 09:16 AM (9 years, 2 months ago) |
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I would recommend putting the the blower between the prefilter and hepa. That's how most are designed and they are designed that way in order to not stress the fan motor as much (to my knowledge, I could be wrong on why they are designed that way though). I doubt you did any damage to the filter. Many of the HEPA's in filter fan units blow more cfm than a traditional laminar flow hood.
Cheers!
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samsxtysix
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Registered: 01/25/15
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Last seen: 8 years, 9 months
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Prefilter is normally on the fan intake so the fan is protected from dust etc
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deadmandave
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Re: Laminar Flowhood question [Re: samsxtysix]
#21409282 - 03/14/15 10:46 PM (9 years, 2 months ago) |
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you can also limit the airflow going into the blower by blocking off some of the intake. sort of ghetto but it works like a charm and means not buying another blower.
if you want to be precise you can wire in a blower controller, even a simple rheostat would do the trick; and you can control the fan speed at that point.
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Val
Were just Marbles in a Cave...

Registered: 01/31/15
Posts: 120
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Re: Laminar Flowhood question [Re: deadmandave]
#21413478 - 03/15/15 09:41 PM (9 years, 2 months ago) |
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Quote:
deadmandave said: you can also limit the airflow going into the blower by blocking off some of the intake. sort of ghetto but it works like a charm and means not buying another blower.
Some Fans have a cutoff that they will enable if the back-pressure is to high, from what I understand... At least thats what it said on my fan when I purchased it for my hood. BYMMV
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deadmandave
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Re: Laminar Flowhood question [Re: Val]
#21413888 - 03/15/15 11:17 PM (9 years, 2 months ago) |
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back pressure? maybe the term is over my head 
the way i understand it, by reducing the intake size, you are reducing the amount of air allowed into the fan, reducing the amount of work the motor must do in order to spin the turbine.
to me back pressure occurs in the plenum, or more commonly for these fans, in long vents where the fan is pushing air up columns and around corners.
here is the wiki definition: Back pressure refers to pressure opposed to the desired flow of a fluid in a confined place such as a pipe. It is often caused by obstructions or tight bends in the confinement vessel along which it is moving, such as piping or air vents.
idk
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knomadic_niki
A mile high



Registered: 06/30/14
Posts: 1,275
Loc: 6200' Colorado
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Re: Laminar Flowhood question [Re: deadmandave]
#21418668 - 03/16/15 11:29 PM (9 years, 2 months ago) |
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you shouldn't put a fan speed controller on a fan that was not designed to have one (came with one). you'll break the motor or worse.
-------------------- My trade list In search of sporeless oyster cultures
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BigE610
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Registered: 09/20/06
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how does the price of building a flowhood compare to buying an entry level one?
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knomadic_niki
A mile high



Registered: 06/30/14
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Re: Laminar Flowhood question [Re: BigE610]
#21432256 - 03/19/15 05:07 PM (9 years, 2 months ago) |
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idk how much an "entry level" flow hood is but i paid $300 to build mine
-------------------- My trade list In search of sporeless oyster cultures
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deadmandave
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Yeah, probably half price or less if you're thrifty. You can obtain a blower from old furnaces and then all you need is a filter (~$100-150) and wood.
BTW you can use a motor controller on fans if they do not have a capacitor... Well you can get away with it even if they have a cap but make sure it is on full speed when you power it on then dial down
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knomadic_niki
A mile high



Registered: 06/30/14
Posts: 1,275
Loc: 6200' Colorado
Last seen: 6 years, 9 months
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Re: Laminar Flowhood question [Re: deadmandave]
#21439823 - 03/21/15 02:48 PM (9 years, 1 month ago) |
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i was told not to put a fan speed controller on fans w/out capacitors by an electrician. i guess you can get away with it but from what i understand its a fire hazard and you can burn out the motor. i'm not an electrician, though. this is just what i was told when i looked into it
-------------------- My trade list In search of sporeless oyster cultures
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