G
greenmatter
you should read scrogers post try doing what he says.
pull or push air through scrubber
- Thread starter Thread starter bigwity
- Start date Start date
ive got a 6 inch turbo fan and a 4 inch scrubber so ive reduced the size down with a carboard sleave. there is no space,heat or any other issue my fan is real powerful so ill be pulling. i was gonna rep any1 who helped me on this thread but there are to many of you!
i love you guys proper quality cheers. bigwits
i love you guys proper quality cheers. bigwits
Ok then Newton was wrong all along! for the past 200+ years physics have used this law to put man in space stop satellites from falling to earth and explain why airoplains stay up in the air and why boats float ect.. but when it come to Grow room ventilation its all BS.
There is more to it than Newtons 3rd Law. It is more efficient to pull through the filter, having your fan near the end of the exhaust system, than it is to have your fan push through the system and filter. I suggest checking out the following book if you care to see the research and data. "Industrial Ventilation: A Manual of Recommended Practice"
Ok then Newton was wrong all along! for the past 200+ years physics have used this law to put man in space stop satellites from falling to earth and explain why airoplains stay up in the air and why boats float ect.. but when it come to Grow room ventilation its all BS.
be careful many scientists are debateing newton now after the evolutionary jump man seems to of made, thousands of years ago.
we are on about air circulation not air mechanics. using air to lift is different to making air move. the same principles may not apply
and dont get stressed its a debate not a attack on yourself.
hippydan
Member
A lot of good information in here for the newbies, like me! Thank you everyone!
In summary: You can both pull and push air through your carbon filters. It is generally accepted that pulling through the filter is better than pushing air through it. It makes sense if you think about it, helps if you read the whole thread.
In summary: You can both pull and push air through your carbon filters. It is generally accepted that pulling through the filter is better than pushing air through it. It makes sense if you think about it, helps if you read the whole thread.
A lot of good information in here for the newbies, like me! Thank you everyone!
In summary: You can both pull and push air through your carbon filters. It is generally accepted that pulling through the filter is better than pushing air through it. It makes sense if you think about it, helps if you read the whole thread.
good work hippydan!!!!
+rep
G
greenmatter
you may have to slow your fan down so smell does not get through. contact time is very important with carbon filters
G
greenmatter
a fan controller costs about $30-$40 on this side of the atlantic. plugs in between the wall and the fan, you dial in your fan spead
Do not go for a varister fan controller. They make the majority of fans hum.
You need to go for a Transformer type often marketted as silent fan controllers. They work brilliantly. They will not do anything auto for you like increase or decrease speed with climate but just operate on the setting dialled in, here is an example.
http://cgi.ebay.co.uk/SILENT-FAN-SP...arden_PlantsSeedsBulbs_JN&hash=item27a5afc5f9
You need to go for a Transformer type often marketted as silent fan controllers. They work brilliantly. They will not do anything auto for you like increase or decrease speed with climate but just operate on the setting dialled in, here is an example.
http://cgi.ebay.co.uk/SILENT-FAN-SP...arden_PlantsSeedsBulbs_JN&hash=item27a5afc5f9
hi dao, what i mean is that you have to somehow get the white sleave to coat the inside of the pipe that goes into the centre of the filter. so the air you are pushing through gets filtered before going through the carbon.
going from memory, you have space above your cabs, i would cut a hole in the top and then have a mini box sitting on top that houses your fan and filter, then you can pull though the filter.
the top of my cab has a gable that exactly fits the roofspace that is only about 5' tall max. my fan can filter sits up there and i pull air through the filter.
hippydan
Member
You're a genius VG. So glad to have you around! I'm not sure if I'll be able to rig something up like this to work for my setup specifically, but it's a great idea and will definitely help someone out there.
either way works just fine, pushing or pulling, and once the load is established it does not matter to the fan if it is pushing or pulling
the can filter 2600 that was on my 150cab lasted for 3+ years having the air pushed into
...as a matter of fact it's still working just fine but is now in my veg closet with air being "pushed" thru it
like said, if you're going to push thru the filter take the pre filter off the outside and put it on the inside
mj
the can filter 2600 that was on my 150cab lasted for 3+ years having the air pushed into
...as a matter of fact it's still working just fine but is now in my veg closet with air being "pushed" thru it
like said, if you're going to push thru the filter take the pre filter off the outside and put it on the inside
mj
mintz
Member
that works,thats what im doing
My appologies for not reading this whole thread, but may I share some fan thoughts with you.
All things being equal, the fan laws state that the volume of air that a fan puts out is directly proportional to its RPM. A 10% increase in RPM results in a 10% increase in air volume discharged.
Not quite that easy though!
The 10% increase in RPM however required the cube of the increase in horsepower to accomplish it (10% to the third power).
Furthermore any increase in static pressure requires the square of the increased pressure in horsepower (10 squared). That is where filters dramatically change fan output before back pressure shuts down the flow.
More directly to the question of push vis a vis pull through a filter, it really depends on the application.
I always throttle on the inlet side of the fan to get the best efficiency, but you can produce more static pressure on the discharge side of the fan than the inlet side.
Think about how a fan works. It moves air by pushing the air molecule along with its impeller.
What happens when there is negative static pressure and there are less air molecules for the fan impeller to grab hold of and the molecules are further apart so that they have less molecular attraction to one another, so that they drag one another along?
With a fan conveying significant solids, I would put the filter on the inlet side to protect the fan.
If you shut off the inlet side of a fan, the impeller just free wheels in a vacuum and the fan draws less horsepower and electrical current.
Simple axle flow fans (propeller on shaft) will support very little static pressure before just stalling out, so we have to use a centrifugal design which will.
Depending on the design, if you shut off the outlet side of a centrifugal fan, you may very well overheat the motor and trip the thermal overload if the static pressure is high enough and it is rotated close to max RPM for the motor horsepower.
Most centrifugal fan designs that we use in home grow rooms will only support 2 to 3 inches of water column static pressure in the first place however, so they are unlikely to overheat, but they they won't support a whole lot of filter back pressure either.
I'm predicting that you should however get marginally better filter life on the discharge side.
All things being equal, the fan laws state that the volume of air that a fan puts out is directly proportional to its RPM. A 10% increase in RPM results in a 10% increase in air volume discharged.
Not quite that easy though!
The 10% increase in RPM however required the cube of the increase in horsepower to accomplish it (10% to the third power).
Furthermore any increase in static pressure requires the square of the increased pressure in horsepower (10 squared). That is where filters dramatically change fan output before back pressure shuts down the flow.
More directly to the question of push vis a vis pull through a filter, it really depends on the application.
I always throttle on the inlet side of the fan to get the best efficiency, but you can produce more static pressure on the discharge side of the fan than the inlet side.
Think about how a fan works. It moves air by pushing the air molecule along with its impeller.
What happens when there is negative static pressure and there are less air molecules for the fan impeller to grab hold of and the molecules are further apart so that they have less molecular attraction to one another, so that they drag one another along?
With a fan conveying significant solids, I would put the filter on the inlet side to protect the fan.
If you shut off the inlet side of a fan, the impeller just free wheels in a vacuum and the fan draws less horsepower and electrical current.
Simple axle flow fans (propeller on shaft) will support very little static pressure before just stalling out, so we have to use a centrifugal design which will.
Depending on the design, if you shut off the outlet side of a centrifugal fan, you may very well overheat the motor and trip the thermal overload if the static pressure is high enough and it is rotated close to max RPM for the motor horsepower.
Most centrifugal fan designs that we use in home grow rooms will only support 2 to 3 inches of water column static pressure in the first place however, so they are unlikely to overheat, but they they won't support a whole lot of filter back pressure either.
I'm predicting that you should however get marginally better filter life on the discharge side.
