How Aerosol Cans Work
When talking about aerosol cans, “aerosol” actually refers to the cloud of liquid and gas that comes out of the can. An aerosol is a fine mist of liquids—or many fine solid particles—that are evenly dispersed throughout a gas. Fog, smoke, and steam are all aerosols.
About Aerosol Cans
Aerosol cans are a mechanism designed to turn a liquid into a finely dispersed mist. It’s a device that uses one highly pressurized fluid to push another fluid out of the can. To ensure that the product comes out evenly, aerosol can manufacturers have to squeeze the contents into the can with a pump or compressor. Typically the contents are stored at 2 to 8 times normal atmospheric pressure.
Propellants
Liquids are not easily pressurized, but gases are. This is why aerosol cans contain the liquid product and the pressurized gas propellant which helps push the product out of the can and turn it into an aerosol cloud. The liquid product is poured into the can. Then, after the can is sealed, the gas is pumped in at high pressure which causes it to push down on the product.
Valve
When you press down on the button, the valve opens and reduces the pressure at the top of the can. The pressurized gas then tries to escape the can by going up the tube and out the nozzle, but since the liquid is in the way, it pushes that out with it. The nozzle’s very small hole atomizes the liquid, which means it breaks the liquid up into tiny drops, which forms the fine mist we see. However, depending on the type of product and the type of nozzle, this process also works for foams and gels.
