Pressure Difference Means Suction

• Placing a drinking straw into a glass of beverage and then "sucking" that liquid into your mouth through the straw is the same basic principle as a vacuum cleaner. Your mouth is lowering the pressure in the liquid by your intake through the straw. The atmospheric pressure, the force or weight of everyday air, is pushing down on the liquid in the glass, and the liquid is moved up into the straw and inside your mouth by "sucking" on the straw. The pressure at the bottom of the glass is lower than the pressure at the top of the glass, so the liquid will find the path of least resistance and flow in that direction.
  
  

Electric Motors and Fans

• The vacuum cleaner creates a pressure difference by the action of the electric motor that is mechanically attached to a fast-spinning fan. The fan turns in such a direction as to "draw" air into the spinning blades. The intake side of the fan, where the air enters, is a lower pressure than the outtake side, exhaust, of the fan. This movement of air creates a suction on the intake end of the vacuum cleaner motor. The blades of the fan are made in such a way as to help accelerate the moving air into almost supersonic speed. Supersonic speed is typically described as "faster than the speed of sound." This acceleration of air gives the vacuum cleaner its distinctive "whine" when it is running and sucking air through the suction hose.
  
  

Vacuum Chamber and Filter

• Located before the vacuum fan and motor assembly is the vacuum chamber. This typically round plastic tube is where the dust filter is housed. The dust filter is an important element in the efficient operation of the vacuum cleaner since it serves two purposes. Most importantly, it filters the dust and debris collected by the pressure difference of the fan. It also keeps that debris from entering the motor and fan assembly. Failure of the filter can allow dust particles to re-enter the home and debris to destroy the fan and motor. Special designs on the filter chamber can also aid on the amount of suction produced by the spinning fan.
  
  

• Newer types of vacuum cleaners now use an air chamber that can resemble the spinning air of a "vortex." The vortex can actually be seen inside some clear plastic chambers on newer models of vacuum cleaners. The vortex air movement resembles that of a mini-tornado inside the housing. This mini-tornado design seems to improve the efficiency of the suction on some models of vacuum cleaners. It also may extend the life of the paper filters by dropping out the heavier dust and debris into a separate collection chamber. This can reduce the cost of having to regularly replace the needed filter in the vacuum cleaner.