OK- - - -if the inner section is spring loaded, the orfice in the middle sets the minimum flow rate. Higher manifold vacuum causes the entire plunger to move, allowing more flow under high vacuum conditions. That's how all PCV valves work, even the Mickey Mouse disposable ones we have today. That one was designed to be serviced periodically, and last the life of the engine or longer.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!