Making a smoke machine forcefully blast out the smoke.

[Al Skierkiewicz]

Sanddrag,
Try dumping the smoke into a larger volume like an old bellows. Then you just presurize or squeeze the volume down to make the puff. Maybe a drum with a piston inside that you pull up to puff. I am assuming you are shooting for a "dragon breath" kind of effect. Compressed CO2 produces a nice effect, like from a fire extinguisher, too. If you already have compressed air, you may be able to use the first idea with the compressed air in a venturi type of vacuum that pulls the smoke out of the storage container. It might work but give significant turbulence.