How Do Aerosol Cans Work?

Aerosol cans actually have two fluids stored inside. One is called the propellant and the other is referred to as the product. The principle behind aerosol can is that the propellant which is in the state of gaseous form will push or drive the product, which is in liquid state, out of the can when the head piece of the valve which is located at the top of the can is pressed.

There are actually two types of gas propellant used in aerosol can - compressed gas and liquified gas. The design for both gas systems is the same. The liquid product is first poured into the can and sealed. The gas propellant is then pumped through the valve system at high pressure so that it pushes the liquid product down in the can with such a good amount of force. A dip tube is connected to the valve at the top that extends all the way down to the bottom of the can. This is where the liquid product exits when the button at the top of the can is pressed.

An aerosol is, by definition, a suspension of particles of liquid or solid that exist dispersed in a gas. In common usage, this is what is produced by an aerosol can but fog is a natural example.

Aerosol cans contain substances such as scent or cleaning fluids packed under pressure. They are fitted with a device that releases the aerosol as a fine spray. Pressure in the can acts on the surface of the liquid contents, forcing them down. This forces the liquid into the bottom of the tube that leads from the plunger at the top of the can down to the bottom of the inside of the can. When the plunger is pressed, the liquid in the tube is forced out of the small hole as a fine spray.

As the liquid sprays from the can, the small amount of propellant dissolved in the liquid vaporizes, producing a fine spray of small droplets.

Most aerosols used to use chlorofluorocarbons (CFCs) as propellants but these were found to destroy the ozone layer in the upper atmosphere and have now been banned.