Observation and Measurement of Aerosol Spray Dispensers Using Digital Microscopes

Advantages of aerosol spray dispenser products

• Easy to use by simply pressing a button.
• Easy to carry around.
• Long-term storage is possible because contents do not become oxidized.
• Safe and sanitary due to dirt-free structures.
• Just the necessary amount can be used.
• It is possible to create finer mist or foam than pump-type dispensers.

Disadvantages of aerosol spray dispenser products

• Containers may burst when left in locations exposed to high temperatures.
• The gas pressure reduces at low temperature, preventing contents from being discharged powerfully.
• Aerosol spray dispensers need to be separated when they are discarded.
• Contents may be left inside when the gas is exhausted first.

Products shaken before use:

• Products that use liquefied petroleum gas (LPG) or dimethyl ether (DME) as the propellant
• Products in which the propellant does not dissolve in the liquid and thus there are three separate phases
• Products that contain an emulsified liquid
• Products that contain a liquid mixed with powders

Products not shaken before use:

• Products that use a compressed gas, such as nitrogen gas (N₂) and carbon dioxide (CO₂), as the propellant

Products that cannot be used upside down:

• Products that spray a contained liquid through a dip tube
  This structure cannot be used upside down because the dip tube tip enters the propellant gas layer.

Products used upside down:

• Products that do not have a dip tube
  This structure cannot be used upright because the propellant gas layer is on top.

Products that can be used upright and upside down:

• Products in which the dip tube is weighted.
  The dip tube tip is always immersed in the liquid phase.
  
• Products that have a mechanism to discharge a contained liquid not only from the dip tube but also from the hole on the valve side wall (vapor tap)