How to slow my dump and fill valve speed?

[edflores]

Originally Posted by Shane

not to be argumentative homi, but that is incorrect. take a peep at the spec tag on the air compressor in your work shop. notice how the higher the pressure the lower the CFM rating is.

Boyle's law states that when pressure on a sample gas (ambient air in this case) increases the volume decreases proportionately if the temperature remains constant and visa- versa.

P.S. I'm curious about the no shock thing as well.

I think he was refering to mass air flow, not cfm.
According to wiki:

"The term cubic feet per minute (CFM) is ambiguous when it comes to the mass of gas that passes through a certain point because gas is compressible. If the pressure is doubled, then, for an ideal gas, the mass of the gas that passes by will also be double for the same rate of flow in cubic feet per minute".

So even though CFM goes down, the mass of the air goes up. So in reality, more air is being passed.

Also, I dont think the compressor analogy would apply here. A compressor is fighting to fill a tank that is at a psi slightly lower than the output. It has to build up.

Air flows to the path of least resistance, and evens out. A bag at zero psi will react more, than a bag at 150 psi.
Also, a tank at 200 psi, filling a pair of bags will go down to lets say 150. bags and tank will be at the same pressure. Dump, and fill the bags. Second time around got a bit slower, and the bags may have only gone to 100. 3 time around, you'll notice that it barely moves. Therefore, the less pressure, the slower the rate of air flow.
I think we all know what we are talking about, just not the proper terms to put it in so we all understand. I think I'm on the right path in my thinking.

[Shane]

you do realize that CFM is a unit of measure for flow, not mass, in relation to Boyle's law, yes?

[edflores]

Originally Posted by Shane

you do realize that CFM is a unit of measure for flow, not mass, in relation to Boyle's law, yes?

Yep.
But we have to adress other factors then CFM, because cfm does not address mass.
Boyle's law refers to a closed environment. A tank, is being fed from outside and is open to incoming air.
Air density goes up as the pressure goes up since the volume is fixed.
I think I am having a hard time explaining it. But we need to look at the mass of given air.
But CFM might not be the right term to use here.
Maybe this:
http://en.wikipedia.org/wiki/Mass_flow_rate
Not trying to argue with you Shane, because you are correct in your points. Just trying to help explain why air moves "slower" at 150 vs 200.

[Shane]

I totally agree with you ed, air does move slower (velocity) at 150 versus 200 psi but that is also determined by the orifice/venturi that it is forced through. But that is a different debate altogether. LOL

My point was only that a 1/4" line does not carry the same amount of air at a given pressure that a 1/2" line carries at the same pressure. Although the pressure (psi) is the same, the volume (CFM) is not. And without the volume, the pressure is meaningless.

Think of it in terms of a water line ... a whole lot more water comes out of a 4" fire hose at 10 psi versus the amount of water that comes out of a garden hose at the same 10 psi.

I don't take is as arguing ed ... it's all good brah!

[charx2]

Ok, I guess I will open my lines up again and put maybe a smaller line inside if I can find one that fits, that should slow down my fill a bit. I will repost when I finally get around to doing it but it might not be for a while, still have much to do! Thanks for you help guys.