how vacuums work
Many of us illustrate the way a vacuum works every day. When you sip soda
through a straw, you are using the most basic of all suction systems. Sucking
up the soda causes a pressure drop between the bottom of the straw and the top
of the straw. With greater fluid pressure at the bottom than the top, the soda
is pushed up to your mouth. Although the vacuum cleaner design is a lot more
complicated, the same general principles apply.
Here's what happens when you plug in the vacuum cleaner and turn it on:
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First, the electric current operates the motor. The motor is attached to
the fan, which looks similar to an airplane propeller.
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As the motor runs, it turns the fan blades. As the fan blades turn, they force
air forward.
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When the air particles are driven forward, the density of particles (and
therefore the air pressure) increases in front of the fan and decreases behind
the fan.
The pressure drop behind the fan is just like the pressure drop in the straw
when you sip from your drink. The pressure level in the area behind the fan
drops below the pressure level outside the vacuum cleaner. This creates suction
inside the vacuum cleaner. The air pushes itself into the vacuum cleaner
through the intake port because the air pressure inside the vacuum cleaner is
lower than the pressure outside.
As long as the fan is operating and the pathway through the vacuum cleaner is
unobstructed, there is a constant stream of air moving through the intake and
out the exhaust of the vacuum. This stream of air acts just like a stream of
water would. The moving air particles rub against any loose dust or debris and
the friction created carries the material through the inside of the vacuum.
Upright vacuum cleaners usually have rotating brushes at the intake nozzle to
agitate the carpet fibers and loosen dust and debris. This helps the vacuum
pick up dirt more effectively.
Also affecting the air flow and suction power is the carpet height adjustment.
The ideal carpet height adjustment setting will provide a tight seal with the
carpet to optimize air flow, but not so tight that it will bog down or stop the
rotating brush.
As the dirt filled air makes its way to the exhaust, it must pass through a
filtration system. Just like you might guess, the filter acts as a sieve to the
air. Filters have different filtration ratings that are based on how
effectively they capture dirt particles before releasing the air back into your
home.
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