air compressor question.

[glen box]

I just picked up an old ac. (Freebee);) It is a 1955 Wards 40gl horzontal. I know the cpfm out put is not going to be much. But I was wondering. How can I measure the cpfm output. Are there gauges for this?

[Lee Schierer]

I read a while ago:
Calculating compressor discharge capacity can be difficult as it varies according to discharge pressure, however piston displacement is easier.
CFM= HEA X S/12 X rpm for single acting cyl
where:
HEA head end area
S stroke (inches)
CFM= 2 X (HEA-RA) X S/12 X rpm for d/acting cyl
where:
HEA head end area
RA rod area
S stroke (inches)

and:

As a general rule most compressors produce 4 CFM/HP at 100 PSI.

[glen box]

4cfm/hp so is that 4cfm devided by hp or per hp

[Tom Veatch]

4 CFM/HP => 4 CFM for a 1 HP AC, 8 CFM for a 2 HP AC, etc.

Since the actual volume of a gas is highly dependent on temperature and pressure, volumetric rating are usually in SCFM (Standard Cubic Feet per Minute (http://en.wikipedia.org/wiki/SCFM)). That means that the actual measured output volume is corrected to standard conditions. Therefore, piston displacement X the number of times the piston cycles per minute should give you a reasonably close approximation of the upper limit of SCFM (or CFM of "free air") output of the compressor.

Tool consumption is also usually stated in terms of SCFM (or CFM of "free air") and pressure.

[glen box]

If i remeber I thing it only has a 1hp mtr. It looks like this old dawg is only going to be good for nailers and blowing dust. Which is ok for now. Heck it was free. I do want to run sme other air tools in the future like sanders, drills and impact guns. Sounds like a good xmas present to me.