Originally Posted by SaintsEnd
So I'm wondering as well, if there is a way I can hookup tubes in a way that the fans can help move stuff through them...
Its generalized and broad because there is no actual system... yet... still need to find the right parts, moving oats and whatnot.
Also yes, I didn't realise static pressure didn't help with suction, thats probably the most important aspect of the fans that I need, The size of fan could be 120mm or 140mm
All the air is blowing from bottom to top.
ok... not sure if you are understanding what we are saying and still not sure what type of contraption you are trying to build so we are going back to the basics
CFM = cubic feet per minute. it's the rating of how much air is moved at the given rate. a 100 CFM fan will move 100 cubic feet volume of air (at STP or standard temperature and pressure) per minute with no airflow resistance. CFM rating is affect by the amount airflow resistance so the more airflow resistance it encounters (air filters, obstructions, etc) the lower the actual CFM becomes. however, the counter to air flow resistance is static pressure. if the air that is being moved is pushed by a high static pressure then the amount of reduction due to airflow resistance is minimized. so with high static pressure, the airflow resistance may only diminish the airflow by a small percentage instead of a large percentage.
static pressure is the amount of force the fan exert upon the air that is in the system. it is also the vacuum force applied on the intake side of the fan. static pressure is generally measured in pascal or PSI(pounds per square inch) or other measurements such as mm/h2o(millimeters of water) which is a variation of barometric pressure measurement that is measured in mm/hg or millimeters of mercury. computer fans generally use mm/h2o when giving static pressure information but occasionally you will be given other units of measure which you have to use google to convert the units.
so given that, if you have high static pressure, you will have a higher percentage of the rated CFM pass through the system. lets say you have a given airflow resistance (air filter) with a low static pressure fan, only 40% of the rated CFM has enough energy to overcome the airflow resistance of the air filter. however with a very high static pressure, the fan may generate enough pressure to push 90% of the rated CFM pass the same air filter. this is only a very basic illustration of why we need to know what kind of conditions and components we are working with so we can give you a best guess of what you may need. however if the project must remain undisclosed, we can only give you the information you need to make your own judgement of what needs to be done in your situation.