A tire changer's bead blaster system delivers a large volume of highly pressured air into the cavity of a tubeless tire to help "seat the beads" of the tire to the wheel assembly. Many tubeless tires have extremely stiff sidewalls and the beads of these tires will not seat properly by just pumping air through the valve stem. (Even with the valve core removed)
The "bead blaster" system of the modern tire changer takes the place of the "spray ether and a match technique" used by tire people with no regard for their own safety. See movie clip below.
All tire changer bead blaster systems operate in the same basic way, but the Atlas® tire changers utilize a special internal hose and oversized tank system that delivers up to 50% more volume and pressure than most competitors' bead blaster systems.
Compressed air is stored in the external tank until that air is needed for the bead blaster. The delivery of the air is controlled by a foot pedal on the machine. When the pedal is partially depressed, the air flows into the tire through the hose attached to the valve stem. When the pedal is fully depressed, a large volume of compressed air is "blasted" into the cavity of the tire through holes located on the turntable slide mechanism. (Just behind the clamping jaws). This blast of air occurs while additional air is being introduced through the valve stem inflation hose. The combination of the valve stem air supply and the "bead blasted" air is usually enough to seat the beads of the most stubborn tires.
The "blast" of compressed air applies pressure to the top sidewall, temporarily seating the top bead of the tire to the rim. The large volume of compressed air is then directed toward the bottom sidewall and the lower bead of the rim. This process takes less than one second in most car and light truck cars. The continual flow of the air through the valve stem maintains the pressure against both beads; forcing them to seat permanently and allowing the tire to be inflated to the correct pressure.
To better understand how the bead blaster system works; picture yourself blowing up a balloon. Minimal constant air pressure will force the balloon to slowly inflate. That is how the inflation hose (attached to the valve stem) operates. If the balloon has been inflated recently or the balloon material is very pliable, not much air pressure is needed to fully inflate the balloon. However, if the balloon is new and has never been inflated, you must do one of two things to properly inflate the balloon. You can either"pull and stretch" the balloon to make the material more pliable (That's tough to do on a car tire); or you could just SNEEZE into the balloon (if you could fit it over your nose and mouth at the same time). The huge amount of air volume and pressure would inflate the balloon almost immediately. The "bead blaster" in a Atlas® tire changer actually "SNEEZES" into the tire cavity, forcing the beads to seat properly.