What Makes Vacuum Cleaners Suck?

Vacuums and Suction

All vacuum cleaners operate on the same general physical principles, even though marketing would have you believe that not all vacuums suck the same. Most vacuum cleaners contain an intake port, exhaust port, electric motor, fan, vacuum bag and housing that contains all the components. These act together to clean up whatever it is you point your vacuum at. The most important component to understand is the fan, which actually creates the suction used for cleaning.

Fans, Intake Port and Pressure

When you turn your vacuum cleaner on, the fan turns on and the fan blades begin to turn. These fan blades force air forward, out toward the exhaust port. This causes the air pressure to increase in front of the fan and to decrease behind the fan. In the same way that creating a partial vacuum in your mouth enables you to suck things out of a straw, the vacuum cleaner creates a partial vacuum in the housing, sucking up dirt. The ambient air pressure is higher than the pressure behind the fan, and this ambient air pressure then pushes into the vacuum cleaner through the intake port. Vacuums that suck harder have stronger fans and cost more than cheaper vacuums.

Moving Air and Friction

If the debris is light enough, the ambient air pressure pushing into the vacuum (thanks to the partial vacuum inside the housing) will pick up dirt, due to friction between the particle and the moving column of air. This friction between the rushing air and the dirt makes the dirt rush into the bag. The dirt stays there, while the air flows out through the porous holes in the vacuum bag. To increase sucking action, some vacuums use brushes, either rotated by air pressure or by the motor, to kick dirt and other particles into the air, better enabling air friction to sweep these particles away.

References

• How Vacuum Cleaners Work
• HEPA Vacuum Cleaners - Do They Really Work?
• How Vacuums Work

Resources

• Vacuum Cleaner Last for 70 Years