How do you make your compressorless system work, when all valves "bleed" air slowly?

[kmcclary]

Testing has shown that every valve we've got (SMC dual coil, Festo, RexRoth, etc.) ALL bleed air out their exhaust ports (albeit slowly) in normal operation. We've tried a number of copies and they all act the same. Tiny amounts for sure, but we can watch the air "slowly sink ino the West" as we watch!

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You can see this effect by adding a short hose to the exhaust(s), and covering it (them) with your thumb(s) for a few seconds. It'll always "pfffft" slightly when released. WHICH port moves back and forth on the SMC dual coil units depending on which side is active, but they all do it. (We had hoped it was only an effect of the single coil units, but no such luck... Darn...)
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We wanted to go without a compressor, but how the heck have you guys kept your compressor-less system from bleeding itself low/dry, expecially from just waiting around for the round to start??? Our application's need is just too close to the storage capacity to risk wasting even a little bit of the stored air!

I'm assuming this has to do with the piloted valves' design(s).

As a soluion, I'm considering tying all the vents together, and hooking on a freshly made copy of my old Servo Controlled Valve on the output to "seal the system " until we need to use it (see: http://www.chiefdelphi.com/media/photos/26363 ) , but there's got to be a faster/better way than resorting to that! [Making a Servo Controlled Valve] will take time to implement, which we can't really afford right now this close to ship.

Any proven solutions out there?

adTHANKSvance!

- Keith McClary
Chief Engineer, Team 1502 "Technical Difficulties"