Air Compressor CFM Question

[70runner]

I have a 25 gallon 5hp compressor. I also have two 25 gallon air tanks. If I run these in-line so I increase my capacity will that increase my cfm so I can use air tools that require more air?

Thanks,
Pete

[tcodi]

theoretically, for a short period of time your cfm capability will be higher. (for instance, if you dumped both tanks over a period of a minute, you would have had about 30 cfm, but the pressure wouldn't be consistent).
In reality you couldn't get that much through wimpy little 3/8 air lines, but you could run tons of air for the short period of time that the tanks will be charged. . . .then you rely on the motor.

[70runner]

Thanks for the responses,

what if I run two 5hp air compressors into a central tank. Will the cfm be higher? Would it then be equal to the two output cfms added together?

[Bob Parmenter]

Cfm is a function of the pump output, not the storage vessel size. With more storage you'll be able to work longer the first time, but then it'll take longer to refill. Two compressors will theoretically fill twice as fast, but each is still only putting out what it is built to do. If you want more cfm, get a high cfm pump and motor adequate to drive it. With a 6 cfm pump you won't keep up with a sander, HVLP gun, or any of the other high volume users.

e.g. My compressor does 24 cfm @ 100psi. I can be using a d.a. sander, empty the 80 gallon tank, and it refills in less than 4 minutes. In real operation it doesn't empty the tank before it restarts the pump. The benefit of a high volume pump is, it will refill the tank WHILE I'm still using a high volume air hog like the d.a.

[Henry Rifle]

Bob's right on. More tanks only means you get more time to run the DA, but it takes an equal amount of time to fill the tank after it goes "flat." You get no net gain in work time.

what if I run two 5hp air compressors into a central tank. Will the cfm be higher? Would it then be equal to the two output cfms added together?

Yep. Compressors in parallel are additive - or at least theoretically. The flow not work out to be twice the as much as one, but it will certainly be more than you get from a single unit.

I've seen several shops with more than one compressor feeding a single line.

If that's all you have, I'd give it a shot and see what happens.

[robot]

Bob, give 'em the water analogy......city builds another 1 million gallon tank, does it mean your shower drowns you?

You put in 2 inch pipe instead of your 1/2 Home Depot stuff

Your meter pressure regulator breaks and you get 125psi water.

all three different

mike in tucson