OT.....measuring air usage

Hello,
I am looking for a way to monitor air usage of a pnuematic spool valve. I am an avid paintball player and pretty good gun tech. I have been working on a few projects and one is increasing the efficiency of a marker without restricting flow. One of the hardest things to do is get a true measurment of efficiency. So, I thought if I could measure how much air was being used per shot I could calculate efficiency........ I have some PLC's, analog cards, and displays laying around and though I could impliment them into the process. Maybe some type of low flow flow meter????

Thanks,
Micheal

There are a couple ways to do it
1. Use air tank with known volume - pressurize - read pressure with a GOOD guage that is ACCURATE and has good resolution say .5 or .1 psi. Every time you trigger the device take before and after pressure readings and then use PVT = PVT to calculate volume.
2. Use a good ball type flow meter and record the readings. Connect to exhaust of your device. Make sure it never pressurizes so that you get good readings (pressure throws them off since they are cal'd to Standard Temp and Pressure). You can use a regular balloon to limit the pressure surges.

Dan Bentler