Vessel Inert Gas Blanketing and 'Push Pull System'

Hi all,

Are there any distinctive differences between inert gas blanketing and inert gas push pull systems? The only thing comes to mind is that one will use IG blanketing in storage vessels where there are not much variations in operating conditions. And the IG push pull system will be used in vessels where flexibility is required due to the constant variations in operating conditions.

Do anyone have any process diagrams to show what does a generic push pull system look like?

Thanks!