Canned Thunder: Yes. Surge-Driven Equalizer: No.

I have to make a retraction of what has gone before so I can clear the way for better idealizations of the in-tank equalizer.

The idea that a surge of tank energy will drive the equalizer pressure above tank pressure seems wrong once viewed in the context of this simple law of nature: a lower pressure gas doesn’t spontaneously flow into a higher pressure. I got hooked on the idea that equalization with tank air would cause the equalizer and tank air to arrive at equilibrium, which would then be bypassed in the equalizer because of the heat of compression. It is a superficial idea based on not thinking critically enough.

What really happens is that compression heating in the equalizer does take place when tank air slams into the equalizer, but it contributes to the pressure rise in the equalizer that only reaches the point of equilibrium and stops. My analogy of the pendulum is wrong because the pendulum does not encounter an increasing resistance as it moves toward the equilibrium point.

I could blame senility but it was really just carelessness and wishful thinking, wanting to be the discoverer of a new scientific principle.

That hasn’t changed so I’ll just say that the pressure equalization equations I have been learning are still valuable to the continuation of my work or play. Now that I know that the immediate result of mixing air masses results in equal pressures in both containers—barring other influences—the equations I was working on are now much better as there is no longer any fill-in-the-blank value throwing wishful guesswork into the math. Final tank and equalizer pressure are now equal and easy to solve. The only manually filled-in values are now the initial values of both vessels. The math might still be simplistic from an engineering viewpoint but I think it’s a solid starting place for now. I have to work on the dynamics of flow per time, it is something I’ve never studied.

I have plenty of ideas for new cheaper ways to compress air, aided by the existing pressure in a pre-filled tank and a second much smaller tank or equalizer inside the tank that is fed by a compressor that works against lowered resistance, not against tank pressure. My favorite right now is a movable intake check valve to the equalizer, comprising a piston with a check valve in it. After equalization, an outside energy source pushes the equalized air the rest of the way into the tank. This comprises a compression stroke that is mostly delivery so the PV change work is very small.

I have worked out the math on that so will put it on the blog. I will post the simplified equations for unbalanced pressure equalization too, since it’s still true that thermal effects take longer to even out than pressure equalization which takes place more quickly, or very quickly in an application like this where the two vessels are much different in size and initial pressure.

The most interesting aspect of unbalanced equalization is that if done in the tank as I suggest, the heat of compression is easy to conserve. That has always been the real ideal of what I’m working toward. A cheap way to compress air.

Thanks to everybody for their comments.

Luther