Fans for homemade carbon scrubbers?

Computer fans have been reported not to have enough pwer behind them to be able to move air through a scrubber. People usually have to buy an inline fan which is much more powerful and suited for scrubbers. Then again it's more expensive.

Your current system of 1 fan in 1 out is an active intake active exhaust. If your using 2 fans it would be more effect with a passive intake and active exhaust . THis means holes for intake and fans for exhaust.

With your dilemma of the scrubber, you might be able to attach both fans to the scrubber to pull air through. One at the front blowing air in, and the other at the back sucking air out. using just some holes cut in the bottom or something as your intake- you may need a bit of ducting for this. that would be the cheapest set-up.

 

The heat won't change much if you change to an active exhaust, passive intake. I suggested this so you can use both your fans.
Any ducting or obstructions you put in your exhaust system will put strain on the motor of the fan. Remember these were designed to move a tiny bit of air out of a tiny space with no ducting at all. But give anything a go - you might find the right combination that works for your set-up. How big are your fans - 100mm - how big is the scrubber?
Pics would help.

 

It doesn't really matter too much where you put it, so log as you pass the exhausted air through it.

It's probably easiest to put the filter inside the grow chamber, and then duct that to the two exhaust fans. You might want to put a "prefilter" (like cotton-wool, or acoustic foam, or something) before the carbon, to catch large particles in the air, and extend the life of your activated carbon.

It's better to use both small fans as an active exhaust. If the chamber is air-tight, you will replace your air twice as fast as using one for the intake, out for exhaust.

So long as you can replace the air once every three minutes or so, you should be okay.

-mu

 

One end of the scrubber has a cap, thats right. The air is pushed or sucked into the middle of the scrubber via the open end - the air then is dissapated out through the carbon and wire.
THis is when the air is filtered. Most people use fans to push the air into the scrubber - having the scrubber sitting outside the grow area, then the air is just blown out the scrubber - but since your having issues with fans and want to put a fan on the other end to help with the air flow......
you would have to add an outer chamber to the scrubber for the air to be collected in and then sucked out the other end - don't remove the cap you have on the scrubber and attach a fan, this will make the scrubber useless, and it won't have any air passing through the carbon.

 

I don't think so. If that was the case, the "pre-filter" sleeve would be on the inside, wouldn't it?

-mu

 

This image (adapted from "jasons-indoor-guide") illustrates the principle clearly. The brown arrows are dirty air, entering the carbon filter's side. The blue arrows are clean air, passing through a "cool tube" light, and being exhausted out the right hand side. The cool-tube is optional.

There would generally be more ducting on the right, leading to wherever you choose to vent to.

Apart from the sides of the scrubber, everything needs to be completely sealed. You want to ensure that every molecule of air that leaves the grow chamber has, at one point, passed through the carbon layer.

You can put it before or after the fan, that's totally up to you, and depends on the physical area you are working in.

As for intake fans, I wouldn't bother. Unless you are willing to carry out some complex calculations and do a lot of trial and error, a passive intake is far better. If the room is otherwise sealed, a well placed passive intake will provide all the air you need. If you have three small fans, use them all for exhausting air.

Start with a hole just under twice the size of the exhaust. Close the chamber. Listen to the fan, and open the door. If the tone (pitch) of the fan changes, make the hole slightly larger. Repeat until there's no change in tone.

You should be able to feel the air rushing into the passive intake.

-mu

 

My methods i was suggesting was becasue of his current fan set-up and i doubt he has the room to put the scrubber on the inside of the grow area. The diagram is a great set-up if your have that much space but most growers have very limited space and have to adopt their own system that works for them. I was suggesting the same thing but in reverse and a fans on both ends of the system.

 

Yup, both will work, that's why I said "You can put it before or after the fan, that's totally up to you, and depends on the physical area you are working in". I just figured it was a useful illustration, to fix the idea of the air passing though the filter.

I guess the reason carbon filters are primarily designed to go before the fan, is that most fans pull air better than they push it. As I see it, intake fans are a luxury, and most people don't need them. If you can get a nicely matched pair that run smoothly together, go for it, but a simple hole works fine. If you're working with small (pc) fans, it's probably better to use all the fans you can to get that CFM as high as possible, shift more air, but to be honest, I don't know a lot about pc fans, so feel free to set me straight.

It's easy enough to wing a carbon filter. How about this (just for fun)...

Inside (or outside!) is a long box shape, as long as you need to house all your fans. One (long) side of the box has holes for the fans, the opposite side is two layers of mesh. Between the mesh is activated carbon, say two inches thick. Apart from the mesh and the fans, the box is sealed. (you could also fit your 12V DC pack in there if you are feeling funky, have a simple mains cable escaping the side - if you do that, post pics!)

Simply fit the "pc fan scrubber unit" along the top edge of the grow chamber, inside (with air going carbon>>fans>>outside) or outside (with air going whichever way you prefer); either would work. A quick sketch of the side view for such a theoretical scrubber is attached.

-mu

ps. remember to put a fabric filter at the point where air enters the carbon, to catch large particles, and prolong its life.

 

Just for further study if anyone else comes across this thread looking for the same solution the here it is.
 
The fan you'd be looking for is a Vantec Tornado they are LOUD, although in a cabinet attached to a DIY activated carbon filter even with like an inch and a half of activated carbon these fans will do the trick. Also I couldn't imagine in a cabinet 1 of the fans being too loud. Just be sure NOT to put the filter on the intake of the fan or you will get the clogged vaccum effect. As far as I know they are the most powerful on the market and in the USA like $10-15 on newegg.
 
In conclusion. Have you ever had a girl stick her head out of a car window going 20 MPH? Well that's how these fans kick!
 
If anyone finds this useful please let me know...
 
Good luck fellow stoners.
 
If there's a friend with weed, theres a friend in need. Don't have greed, Share your weed!

 

hi,

im running one 120mm pc fan for intake and two 120mm fans for exaust behind a diy scrubber. I found a 1kg bottlle of activated carbon 7 $ at the pet shop. so far its working great. I have a small area similar to yours. Intake down the bottom and exaust out the top

 

likr so