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My flow hood

PostPosted: Sun Jun 07, 2009 5:33 pm
by J_Max
I know, its weird but it's completely functional. The design is mine and it came about from the materials I already had available. Haven't put the hepa filter in yet.

Re: My flow hood

PostPosted: Sun Jun 07, 2009 5:36 pm
by Matt
WOW! :o That's awesome and it looks relatively inexpensive to make. I really like it. I can tell you definitely have some ingenuity!

What did you end up using for the HEPA filter and where did you get it?

Re: My flow hood

PostPosted: Sun Jun 07, 2009 5:52 pm
by J_Max
Matt wrote:WOW! :o That's awesome and it looks relatively inexpensive to make. I really like it. I can tell you definitely have some ingenuity!

What did you end up using for the HEPA filter and where did you get it?


Well, the HEPA filter I bought from Menard's. I don't know if you have them where you are but it's similar to Lowe's or Home Depot. The brand is HEPAtech and its a replacement for an air purifier. It says it catches particles 99.97% effectively @ 0.1 microns. Cost $20-$25! I thought most HEPA filters were expensive and where rated @ 0.3 microns?

And the cost wasn't bad, pretty sure it was well under $200. The blower was the most, the rest is heating/AC supplies and sheet metal, under $70 for that stuff.

Re: My flow hood

PostPosted: Sun Jun 07, 2009 6:03 pm
by renesis
Wow, very creative! Awesome to see some more people joining in on TC lately!

The only thing you have to be careful about on the HEPAs is what air speed they are rated (and tested at). If you put more air speed through it than what it was designed and tested for, the efficiency might go down.

Is the hood on top the pre-filter?

Re: My flow hood

PostPosted: Sun Jun 07, 2009 6:21 pm
by J_Max
renesis wrote:Wow, very creative! Awesome to see some more people joining in on TC lately!

The only thing you have to be careful about on the HEPAs is what air speed they are rated (and tested at). If you put more air speed through it than what it was designed and tested for, the efficiency might go down.

Is the hood on top the pre-filter?


Thanks a lot! :D I took into consideration what you mentioned about the rating and air speed for the filter. The blower is a monster of an air mover so I constricted the airflow @ the output to 3in then transitioned to 6in. Thus, less speed and pressure. Just enough to go through the filter and purge the work area, assuming that the problem would be with too much air going through it. Hope it works out!

And, yes the top is the pre-filter box. -Max

Re: My flow hood

PostPosted: Sun Jun 07, 2009 7:34 pm
by WORMSS
Matt wrote:it looks relatively inexpensive
Another way of saying "Cheap"??
lol

Squeezing the pipe to slow the air would just put more Strain on the air pump wouldn't it???

could always do something like a Y shape, one 1 half have the air filtered, the other half have a valve.. so some of the air being pushed is allowed to escape and so slows the air going through the filter???

Re: My flow hood

PostPosted: Sun Jun 07, 2009 8:04 pm
by J_Max
WORMSS wrote:
Squeezing the pipe to slow the air would just put more Strain on the air pump wouldn't it???

could always do something like a Y shape, one 1 half have the air filtered, the other half have a valve.. so some of the air being pushed is allowed to escape and so slows the air going through the filter???


Yes, applying constriction on any duct using a blower(not a flat blade fan) will cause the motor to reduce RPMs. But, the blower I'm using is designed for furnace exhaust and is pretty tough. I can get away with about 5/10 of static pressure bogging it down and it won't hurt it a bit. The reason I can't have a relief valve is because although the cfm's would be the same, the static pressure wouldn't be and the pressure is what moves the air through the filter. Not cfm's. With constriction, you 1. reduce rpm's of the motor 2. thus reducing the cfm output of the blower and then pressure:) :)

Thanks for the input tho

Re: My flow hood

PostPosted: Sun Jun 07, 2009 8:18 pm
by renesis
WORMSS wrote:
Matt wrote:it looks relatively inexpensive
Another way of saying "Cheap"??
lol

Squeezing the pipe to slow the air would just put more Strain on the air pump wouldn't it???

could always do something like a Y shape, one 1 half have the air filtered, the other half have a valve.. so some of the air being pushed is allowed to escape and so slows the air going through the filter???


I had a similar problem when constructing mine, but the correct way to do it is by constricting the inlet. Having a relief valve between the HEPA and blower may cause some turbulence. Restricting the inlet works fine as long as the motor has enough air to cool itself. Especially with the motor exposed, he should be fine with that setup.

Re: My flow hood

PostPosted: Sun Jun 07, 2009 10:09 pm
by jkochuni
Wow, that is like the Frankenstein of flow hoods! Well done!