Carbon Filters: Efficiency/Effectiveness?

home.grower · #1 11-30-2007, 08:24 AM

Hello readers,

I have a query, who wants to help?

So I've been to the grow-shop and picked up a copy of the latest Urban Garden Magazine. I'm smoking a joint and reading an article called 'A Mind Blowing Guide To Ventilation - Part Two'.

Without further ado:

Quote:

Originally Posted by Urban Garden Magazine dot com

'... Blowing air into a carbon scrubber tends to give an even pressure across the entire internal surface, which leads to lowest average velocity through the filter and therefore best smell reduction. It seems that sucking will draw most of the air through the carbon that is closest to the outlet. This is because the pressure drop across the carbon is greatest where the scrubber meets the ducting. Due to the large momentum of air being thrown out of a duct when you blow in to it, a larger amount of pressure should be available at the far end and should balance out more evenly across the surface. This should result in a slower average speed through the filter material and better smell removal...'
*Page 16 Nov/Dec 2007 UrbanGardenMagazine 004

What do the friendly readers of the forum make of this statement?

Does anyone use a carbon filter in a direction other than sucking?

I've added a lil diagram that explains what I THINK (edit) the author is on about. I'm wondering if my filter will actually be more effective in the other direction.

Actually, are carbon filters designed to be bi-directional?

thanks!

home.grower · #2 12-01-2007, 07:30 AM

No opinions out there?

rmax · #3 12-01-2007, 08:33 AM

Home,

Your drawing is correct.

"Bi-Directional"

Reversible carbon filters exist. I did a google search. I came up with the ProFilter Reversible Carbon Filter - 50.

"
Most can-type air filters utilize 50% of the carbon available by only filtering the top section of the carbon filter, leaving the bottom part unused. PROfilter uses an innovative patented design allowing the user to reverse the filter, benefiting from the use of 100% of the carbon available and directly extending the unit's lifespan.

Manufactured with the finest TC940 virgin 3mm grain sized carbon, PROfilter effectively removes 99.5% of odors. Rated for continuous worry-free operation, PROfilter can be used for commercial or residential applications.
Requires choice of flange."

Micheal Kelso · #4 12-01-2007, 08:37 AM

I keep mine on the exhaust. Mine blows into the filter - seems to work best this way and also is more dampened making it more quiet.

I guess I never thought to suck air through it...

butter111 · #5 12-01-2007, 08:46 AM

if u never sucked air through it how do u know it works best the other way?
and what do the fan mfgs recommend?

Micheal Kelso · #6 12-01-2007, 09:11 AM

I guess I meant that it works good that way, not best.. my comparison comes from just running the fan w/o a filter (real loud) and then with the filter..

The one I have came assembled with the can fan blowing into the filter. I looked at the documents that came with it and it doesn't say anything about reversing it so I guess it is only meant to work with the air blowing into it.

saine420 · #7 12-01-2007, 09:21 AM

I suck it through. Maybe ill try to blow it through. I thought to blow it through, but I heard sucking was better.. First grow I smelt nothing. This one I smell a little, maybe before I buy a new one I'll try to blow through. I heard blowing it through reduces the smell in the place where you exhaust, but your room itself and the surrounding areas smell stays. With the filter in my room sucking the room air through and out you have to put your face to the bud to smell. I will try though.. Thank you!!

home.grower · #8 12-01-2007, 09:29 AM

Quote:

Originally Posted by rmax

'... Reversible carbon filters exist. I did a google search. I came up with the ProFilter Reversible Carbon Filter - 50...'

I'm searching google using the search string 'bi-directional carbon filter' and I'm not quite hitting the nail on the head. Can u post your search string please so I can see what google comes up with, or a link to the manufacturer.

I wonder if the length of a filter and the diameter of the opening have significant impact on the overall efficiency of carbon filters.

My current filter is only around 19" in length and 9" diameter and 6" opening, but my fan is a 8". Am I likely to increase the efficiency of my filter by using a larger extractor?

thanks

Quote:

Originally Posted by Micheal Kelso

I keep mine on the exhaust. Mine blows into the filter - seems to work best this way and also is more dampened making it more quiet.

I guess I never thought to suck air through it...

I've seen a setup featured on the urban grower dot com website where a grower has a dual scrubber in a grow room. I recall 2 huge fans operating in the same direction and 2 huge 12" carbon filters either side of the room. One was sucking while the other pushed air through the carbon. The reporter stated that he could hardly smell the tens of plants in full bloom. Have you seen this setup and I wonder if I put my existing or a second filter inline on the air-out if this will be just as effective

thanks

Quote:

Originally Posted by butter111

if u never sucked air through it how do u know it works best the other way?
and what do the fan mfgs recommend?

Very good question. I don't think I would have thought to ask it, but I'm now on-guard.

thanks

Quote:

Originally Posted by Micheal Kelso

I guess I meant that it works good that way, not best.. my comparison comes from just running the fan w/o a filter (real loud) and then with the filter..

The one I have came assembled with the can fan blowing into the filter. I looked at the documents that came with it and it doesn't say anything about reversing it so I guess it is only meant to work with the air blowing into it.

Who makes your fan and filter?

Thanks all for replying.

home.grower · #9 12-01-2007, 09:35 AM

Quote:

Originally Posted by saine420

... I heard blowing it through reduces the smell in the place where you exhaust, but your room itself and the surrounding areas smell stays. With the filter in my room sucking the room air through and out you have to put your face to the bud to smell. I will try though.. Thank you!!

Same here.. Although from time to time and especially after watering these ladies do let off their sensual aroma.

And rmax, its ok, I had my cannabis hat on and wasn't searching as a searcher should... I've found and I'm about to do a lil reading.

thanks

Micheal Kelso · #10 12-01-2007, 09:45 AM

I bought it used on Craigslist.. the brand is EcoPlus Carbonaire. I don't know the model though since I bought it used.

After looking at the manual that came with it.. I am starting to think I have been running it backwards... The person who had it before me just had it set up with the fan blowing in so I thought that is how it should go.

I looked at some similar ones online and they all have the fan sucking in the pictures...

It makes sense because by blowing into mine, I don't even need the prefilter on the outside because it is only slowing down my CFM.

Now you got me thinking I should make mine suck in, the fan just flips over no problem....