Carbon filters, Do you push through or pull?

[wantaknow]

both one on each end,cya,

 

[qupee]

Wrong. its not like fluid.. Fluid does not compress, thats hydraulics.
There is compression with a fan.

So I can say that there is compression in an air blower/centrifugal system.. thats a fact.

I'll go with a conservative estimate of 1:2 compression ratio. So you're trying to force more air through a filter.. So that in theory should be moving air faster over the filter.. not such a good idea for something that uses adsorption. you would have to make up for it with higher air recycling rates or more surface area.

Observations:
My HEPA filter for the house uses a carbon filter on the suction side of the unit. What you suggest is opposite of a commercial design.

Lastly, there is much less surface area the air first contacts for the if you push into the can. Take the internal diameter of the can and do a cylinder surface area calculation, then take the OD of the can and do a cylinder surface area calc.

I got my own reason why I pull.. Now Im sure there are valid reasons for pushing but unless somebody explicitly explains it correctly with facts and observations I'll go with that.

Seriously? The flow of gases is fluid dynamics. Compressibility is a variable. The air is compressed regardless of what direction it is traveling. Do you think pulling the air from a large opening (outside of filter) to the smaller inner opening doesn't create a pressure differential? What difference does the inner surface make? The air contacts surfaces all the way through the filter, not just on the initial front it makes contact.

 

[whadeezlrg]

I pull through the carbon filter but push through the lighting in an effort to reduce high heat going through the inline fans.

there are a couple good reasons to pull through air cooled lights instead of pushing: 1) if a duct somehow comes loose it gets blown off of the light very easily, when pulling the negative pressure is generally enough to keep ducting in place even if there is a failure. 2) pushing through hoods exposes any air leaks and pushes hot air out into the grow environment(I've personally seen in a friends garden a significant decrease in room temps by pulling instead of pushing through lights)...there's other reasons that i just cant think of at the moment fwiw...just my 2.

also fwiw in my experience, inline fans lasts a minimum couple years of non stop running(none of mine have skipped a beat running for years in the midst of all of the heat produced by 4kws...full speed or ran with a controller) and running an ac to account for any extra heat that leaks will most certainly cost more over the course of the life expectancy of an inline fan(which typically have a minimum 2yr warranty)

 

[rives]

I run both ways (different systems, different requirements) and they both work fine. The one that I am pushing through (bonsai mom cabinet) uses a filter on the air inlet that is changed out monthly, and the carbon filter is just over 4 years old.

 

[Arthritis_sucks]

Can it be done.....yes with putting the prefilter inside with a heavy wire tomato cage like rig to keep the prefilter in place ( hassle an not worth it).

Should it be done........no. works better pulling.

Go science!

 

[noyd666]

phresh filter, pre filter= just fold and round it and drop it in.

 

[rives]

Can it be done.....yes with putting the prefilter inside with a heave wire tomato cage like rig to keep the prefilter in place ( hassle an not worth it).

Should it be done........no. works better pulling.

Go science!

If the setup needs this configuration, simply filter the air inlets into the cabinet/tent rather than trying to stuff the pre-filter inside the carbon filter. It gives you the side benefit of keeping out bugs, etc.

 

[Arthritis_sucks]

If the setup needs this configuration, simply filter the air inlets into the cabinet/tent rather than trying to stuff the pre-filter inside the carbon filter. It gives you the side benefit of keeping out bugs, etc.

Slick.

 

[leedsutd95]

Never had the need to run one, but might have to soon. Had a scout around at a few brands etc. Spoke to a few shop owners and one guy was insistant that you should be pushing through them.

At the time it kind of made sense because I've worked with pumps before (a bit like a fan) and I know the suction head is always less. Like a pump might have 40m of head at the discharge end, yet only 8m of head at the suction.

However, reading around some people have said you should always pull through the filter because there is a prefilter on the outside. I am interested in what people here do. I think the majority of you pull through. Any pushers?

I think its important to note, the shop owner was saying put the fan+filter together with no ducting between up in my roof space.

Here are my two options for setting up my next grow. Any advice?

===== Ducting
X fan
O filter

Option A:
(Tent OX==)============(== Roof space)
or
Option B:
(Tent ===)=============(==XO Roof space)

listen to granger2