WATER FLOWS TO VESSEL Water is stored in an enclosed
tank that contains slightly pressurized air. Water enters the tank at a
much higher pressure, measured in pounds per square inch (PSI) or bars (metric).
VESSEL READY TO FLUSH Water displaces the air, causing
it to further compress until the air pressure inside the tank is equal to the
regulated maximum pressure of 35 psi.
AIR PRESSURE EMPTIES VESSEL When flushed, the stored
energy of the compressed air accelerates the water flowing into the
toilet bowl faster than relying on gravity alone.
Bet you can figure out where “gravity-fed” toilets got their name!
The result — a small amount of water is supercharged into a flushing force
well above its 1.6 GPF/6 LPF weight class.
This water in rapid motion wants to stay in motion. The trapways on
pressure-assist toilets can be enlarged up to a ball pass of 2 1/8 inches
because the momentum of the water cleanly removes wastes without the need to
create a siphon (or the choke point that comes with it).