qev actuation

[steveperson18]

im looking in catalog page 913 of mc-master and i was wondering which qev would be best. my barrel is sleeved in .5" copper pipe, and i was thinking most about the right-angle valves (6646K) on that page.

i dont quite understand why there is 3 measurements (inlet, outlet, exhaust); is this because air can pass through from the inlet to the outlet freely, and the exhaust just vents the air from the center?

also, how are they actuated? maybe air can only pass from the inlet to the outlet when the exhaust is open the the atmosphere (like the blowgun on a modded sprinkler valve?

does anyone else know what kind of store i can buy these at in person (in america)? i tried home depot, lowes, and paintball/sporting goods but no luck.

thanks a bunch!!!

[GalFisk]

A qev is triggered by dropping the inlet pressure below the outlet pressure (the outlet is connected to the chamber). When this happens the chamber is vented through the exhaust (which you connect to the barrel). You usually fill the chamber through the inlet, some qevs also allow the chamber to be filled directly.
The 'best' valve is the one that has enough flow for your application, without being too expensive. The three measurements are of the thread size in each port (input, output, exhaust), bigger is better (there's also a flow measurement on each valve).

[steveperson18]

thank you very much