Vacuum cleaner
Last updated: February 10, 2007.
Even when your house is clean, it's
absolutely filthy! That's
because most of the dust and dirt in your house is way too small to
see.
Fortunately,
most of us can live without knowing this kind of truth about our homes;
a quick run around with the vacuum is enough to keep us happy.
Twenty-first century homes are packed with dozens of appliances and
gadgets, but vacuums are one of the few most of us simply couldn't live
without. We all know vacuums suck up dirt—but how do they do it. How
exactly do they work?
Photo: A Dyson cleaner, like this one, shows you just how much dirt it's picking up. The dust and hair tends to swirl around thanks to the machine's "cyclonic" action.
You can find new and refurbished Dysons like this at AllBrands.com
.
It's all in the name
The name "vacuum cleaner" is a bit of a giveaway when it comes to
understanding how your hoover works. If you've ever tried that cleaning
trick with a tissue paper and a comb, you'll know how effective suction
can be for removing dirt. If not, try it now! Wrap a piece of tissue
paper around a comb. Breath out as far as you can and hold your breath.
Place the comb and paper against your mouth. Now lean against a dusty
armchair and press your mouth and the comb against it. Breath in
sharply so, effectively, you are breathing straight through the comb.
Take
the comb away from your mouth and inspect the tissue paper. See how
dirty it is!
Photo right: Just like a comb and paper. Take the
dust-collecting bin off a Dyson
and you can see one of the filters (beneath the circular grating).
There's
a second filter at the top of the cylinder.
This is almost exactly how a vacuum cleaner works. In place of your
mouth, there's a powerful electric
motor attached to a fan that sucks
in air. (In a typical cleaner, the motor is about 500-1000 watts, so it
uses five to ten times as much energy as a bright electric lamp.) The
tissue paper and comb are replaced by foam filters, and
there's a bag or a plastic bucket to catch the dust sucked in so you
can use the cleaner for some time without worrying about where all the
dirt is going. Most cleaners have a variety of other features,
including a rotating brush at the front (for beating dirt out of rugs
and carpets so it's easier to suck away) and an extension hose (for
cleaning stairs, upholstery, ceilings, and other hard-to-reach places).
From bags to cyclones
Invented in 1901 by a British engineer, the first electric
vacuums were simple sucking machines with a brush and suction head at
the front, a motor in the middle, and a bag at the top. When you
switched them on, the motor whirred into action, sucking in air and
dirt and blowing them into the bag. Most vacuums worked this way until
the late 1980s, when another British engineer named James Dyson felt it
was time to go one better.
The trouble with old-style vacuum cleaners is that they suck in
dirty air and blow it directly into the bag. The bag catches the dirt
and the relatively clean air drifts back into the room. The longer you
use a vacuum, the more the bag fills up. As the bag fills up, the
amount of empty air it can hold decreases, so its ability to suck in
more dirt is gradually diminished. The longer you go without emptying
your
vacuum, the worse the problem becomes.
Dyson decided to tackle this difficulty by doing away with the bag
altogether. By this time, he was already a successful inventor
manufacturing his own plastic garden equipment. His factory in
England's West Country was plagued with dust, so he designed a
"cyclonic" air filtering device to keep it clean. Using a powerful fan,
it sucked in dusty air and spun it around at high speed. Spinning the
dusty air was an effective way to separate the dust out of the air. In
a washing machine, the same
principle is used to
spin water from clothes at the end of the wash cycle. As the drum spins
at high speed, the clothes fling against the edge of the drum and the
water they contain is forced out through the drum's tiny holes. The
same idea proved just as effective in Dyson's air filter. Spinning the
air forced the heavy dust particles out through holes in the filter
where they
could be trapped and collected; the cleaned air could then be piped
back into
the room. Dyson's machine was so efficient and successful that he
wondered why vacuum cleaners didn't use the same idea. He resolved
to invent a cyclonic vacuum cleaner there and then.
Between the late 1970s and the mid 1980s, Dyson built no fewer than
5,127 prototypes of his cyclonic cleaner. By the late 1980s, he was
selling a bright pink cyclonic cleaner called the G-Force in Japan. It
was large, clumsy, and expensive, but it earned him enough money to
develop a more compact, affordable cyclonic vacuum called the DC01.
During the mid-1990s, this new machine won countless design awards and
soon became Britain's biggest
selling vacuum cleaner—and it is now sold worldwide.
Its secret is simple: because there is no bag to clog up with dust and
dirt,
the machine always sucks with exactly the same power.
You still have to empty the dirt bin every so often, but the cyclonic
action
means a Dyson with a full dirt bin works equally as well as one that's
just been
emptied.
All this goes to show that, no matter how good an invention appears
to be, someone can always make it better!
