Ignoramus5722 fired this volley in
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But, I want an answer to my originalquestion,as I do see a big benefit
in what I want to accomplish.


Ok... just put a uni-directional flow-control valve (with a ball check in
it) between the 'main system' and the reserve tank. Control the flow
(slow bleed) INTO the reserve tank, but let it back-flow freely into the
main system any time its pressure is greater than the system.

Then the main system will pump up _almost_ as fast as it would without
the reserve, slowly bleeding air into the reserve as it goes. When
sudden demands occur, the reserve will freely feed the whole system.

Such valves are purely mechanical, one-piece assemblies... ball-check and
flow control (often needle type) valve in one unit.

Lloyd