Pipe System

[ej3243]

Hi, I need some help on a pipe system I have to design.

The system is going to be used to vacumm air from a room.
I need to find what diameter to used for the different pipes to have the more efficienty.
The Fan that is going to be used has a Diameter of Blade of 18" and it has CFM of 4671 with 0.0" Static Pressure and 2163 CFM with static pressure 1".
the air is going to atmosphere.
Total length of system is about 100 feet.
Please if you have any suggestions on how to solve this problem or what formulas to used.
thanks

 

[briand2]

You are using a fan of a few thousand cfm duty. Does that mean you are going to shift something like that amount on a continuous basis (i.e. if you are pulling, say, 3000 cfm out of the room with the fan, will there be 3000 cfm "leaking" into the room)?

I'll try to help if you can give just a bit more information!

Regards,

Brian

 

[saxon]

ej, I don't think that "pipe" would be the system material of choice in this application, but "duct" would be. A good text on the subject is, "Plant and Process Ventilation" by the Industrial Press, New york, Ny.

Hope this helps!

saxon

 

[ej3243]

thanks for helping briand2, the room I am working is real big is about 7000 cubic feet. but what I really want to take out is the gas that comes out of 4 drilling machines. The fan is going to be located in a corner and then we want a duct going in the direction of the drill machines and a hose (about 10'length)connecting to every drill machine from the duct, the machines are align. I need to find what is the best difference in diameters that i need. The info about the fan that i gave you last time is the fan we have bought. thanks for your help

 

[DLANDISSR]

EJ. There is not enough information to do a complete analysis of your needs. I will make some assumptions -
You are trying to exhaust air only and not conveying any chips etc from these machines. The total run of duct is not over 100' and is reasonably straight with few turns.

The minimum inlet velocity should be approx 1000FPM. This means that using the 2163CFM for 4 machines there would be about 540CFM exhausted from each machine. A 10" duct would have a velocity of 990FPM. The 10' hose you mention should therefore be 10"Dia. The second duct size, moving toward the fan, would be a 14"Dia. The third size 16"Dia and the fourth size at the fan 18"Dia. The fan outlet should be 18" Dia. If the total duct and hose length is 100' or less the fan you have purchased should do the job.
This is not meant to be a complete design but a suggestion and estimation of what would be required. I hope this puts you in the ball park.

 

[ej3243]

Thanks for your help DLANDISSR, I still need some help, would this system be efficient if instead of 4 drill machines i have 8 machines. but the total duct and hose still be less than 100'?,
the hose we have is 10' in length and 4" diameter, so I have a total of 8 machines with 8 hoses (10' and 4&quot, and a duct length of 87'.
Do you think the fan (Diameter of Blade of 18" and it has CFM of 4671 with 0.0" Static Pressure and 2163 CFM with static pressure 1&quotI have would do the job???
thanks for you help again.
EJ