calculation

Hello: I was in engineering until 11 years ago and went thru a reoganization then and have been looking for work since to no avail. Anyway I would tell you this if I could get a job for my effort. But, I will go you one better. There is this little black book that a lot are unawhere of. OH, yes many have it but a lot do not. In it is the formula though taken on a educated investigation into the contents of this little pocket book it is what makes a thinking engineer into Sheriff Matt Dillion in many fields of Engineering. Nevertheless, it is a Pocket Ref. Book by Thomas J. Glover ISBN 0-9622359-0-3 Library of Congress 89-90848. Sometimes I have seen it on ebay good used condition. This book is worth the effort obtain and investigate and use in your Engineering battles. Your welcome and keep your job!

Billyjack:

The "little black book", by Thomas J. Glover is available from Sequoia Publishing, Inc., Littleton CO, 80162-0820, 303-932-1400. I recently purchased this from them ('bout $16.00 bucks, if I recall). Handy little book.

The total CFM in what kind of system? A vacuum in what kind of system? Based on your question there is no possible answer, as there are different requirements for any variety of "SYSTEMS"

Is this a homework assignment? Maybe the instructor should be more specific in his/her assignment.

Is this an automated conveyor system, a space station, a ship, a motor vehicle, a train, an HVAC system, etc etc etc. All of the above fit the question yet all have different requirements.

"calculate the total CFM of a system " ??? what system?

calculate cfm in a compressed air system/ cfm free air/ cfm compressed air at dictated pressure/ cfm air in different diameters of pipe/ cfm of air handling units in hvac application etc.

Your question is very vague. There is no one size fits all answer. It all depends on the total area your HVAC system is designed to handle. You need to ask a specific question about a specific environment including total area covered, size and type of the equipment you are using, environmental issues, ie Equator or north pole. All will need different answers. Sorry I can't help any more than that

As the rest of the forum posted, what exactly do you need? a formula? is it compressed air? perhaps you are talking about some general formula. In that case, please be specific or you can do a google search.

SaC.

A flow calculation? A static volume total? cfm at 14.7in Hg or pressurized. Vacuum - hmm 3Ex10^-9or what. bigger than a bread box?

Ha ha ha. I didn't have the heart to ask him this.

CFM = Stroke length in ft. X Cross section in ft². X RPM for a single cylinder reciprocating compressor. Multiply by no. of cylinders if there are more than one.

For other type of compressors CFM = Displacement per rotation X RPM.

This term is usually used for compressors. So I guess this is what you want to know.