Calculating Compressed Air Requirements

What do you want to know?
Are you talking about flow, pressure, safety or what?

I have a manufacturing system that requires air pressure to be a constant 80psi at different intervals, sometimes pressurizing all systems in this one location together, sometimes at separate intervals. It is tied into a common supply from the main compressed air system. I guess my question is what is the volume of air I need to maintain that constant pressure at a given time. I know it is 80psi, but what would I need for storage capacity when they are running separately or all at once. Can I get by with a 30 gallon or do I need to increase it or should I go to a separate air supply to maintain what I need. I know you would probably need to know what is the interval and how much is being bleed off and how many other systems. But If I had a calculator, I wouldn't have to figure it out by pencil and paper and I could quickly re-do it. Any help would be appreciated.

Suggest you check the www.engineeringtoolbox.com under fluid mechanics. They have very helpfull data. Normaly you should size you bottle for the maximum discharge over the maximum duration required before the compressors kick-in to supplement and start the fill up process. Of course you should knwo the individual and collective air consumption requirements of each system and the max required at any given instant to size your system. Let me know if you need more infor after you check the eng. tool box site.

Follow the link: http://www.stealth316.com/2-air-fuel-flow.htm

Since your system is what you can be thought of as a collection of "Things that turn on an off at will", the best practice would be to determine what your MAXIMUM demand air flow. That is, if every stage was operating at it peak how much air in CFM at the rated 80 PSI is needed. Manufactures print/stamp the demand ratings on the nomenclature plate of their producs. Then: First, add up all the numbers and be sure that what ever compressor(s) your using can support this PEAK value. Second, Place one or more accumulators (fancy word for tanks) that will provide 10-20 minutes of air for each of your high demand flow stages. This should is so your compressor(s) arn't running constantly. Compressors rated for high duty cycles (running more then sitting idle) cost a lot more then the store tanks they fill. If space permits I would do like the power companies do. Have one compressor that meets the average demand for your operations and then add one or two peaking pumps to meet your MAX demand. Final point, the larger the pipe between the tanks any you system the better. Because 1/2" pipe won't support 50+ CFM as easly as 1 1/2" does. FYI in Deep Sea Diving we use 1 1/2" - 3" at 150 psi and our nominal flow is less than 50 CFM.

yeh, i agree with mongo, the compressor can be compensated quite alot because of the diameter of the supply piping, but you need to look closely at the consumption of air from the machines.

this will greatly dictate what application you can get away with, the higher the consumption the higher the price!!

Go into sites of Spirax Sarco & Armstrong International and you will find books indicating formulas, charts for compressed air pipeline sizing and air requirements for various machine and pneumatic instruments. Also check Kaiser Compressors.

Once you read thru the notes you will find what you want.

Spirax has an information book on "Compressed Air" request this from UK.

No website will calculate for your compressed air requirements. You should roughly know how much air you are going to consume and accordingly select a compressor with capacity control system and auto discharge pressure control system. Contact any compressor manufacturer for help and guidance.