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home-gad.txt
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1996-04-27
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"HOME TECH": The Inner Workings NewScience
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The Toilet
Yes...those tales you've heard are true. The toilet was first
patented in England in 1775, invented by one Thomas Crapper,
but the extraordinary automatic device called the flush toilet
has been around for a long time. Leonardo Da Vinci in the
1400's designed one that worked, at least on paper, and Queen
Elizabeth I reputably had one in her palace in Richmond in
1556, complete with flushing and overflow pipes, a bowl valve
and a drain trap. In all versions, ancient and modern, the
working principle is the same.
Tripping a single lever (the handle) sets in motion a series
of actions. The trip handle lifts the seal, usually a rubber
flapper, allowing water to flow into the bowl. When the tank
is nearly empty, the flap falls back in place over the water
outlet. A floating ball falls with the water level, opening
the water supply inlet valve just as the outlet is being
closed. Water flows through the bowl refill tube into the
overflow pipe to replenish the trap sealing water. As the
water level in the tank nears the top of the overflow pipe,
the float closes the inlet valve, completing the cycle.
From the oldest of gadgets in the bathroom, let's turn to
one of the newest, the toothpaste pump. Sick and tired of
toothpaste squeezed all over your sink and faucets? Does
your spouse never ever roll down the tube and continually
squeezes it in the middle? Then the toothpaste pump is
for you!
When you press the button it pushes an internal, grooved
rod down the tube. Near the bottom of the rod is a piston,
supported by little metal flanges called "dogs", which seat
themselves in the grooves on the rod. As the rod moves down,
the dogs slide out of the groove they're in and click into
the one above it. When you release the button, the spring
brings the rod back up carrying the piston with it, now
seated one notch higher. This pushes one-notch's-worth of
toothpaste out of the nozzle. A measured amount of toothpaste
every time and no more goo on the sink.
Refrigerators
Over 90 percent of all North American homes with electricity
have refrigerators. It seems to be the one appliance that
North Americans can just not do without. The machine's
popularity as a food preserver is a relatively recent
phenomenon, considering that the principles were known as
early as 1748. A liquid absorbs heat from its surroundings
when it evaporates into a gas; a gas releases heat when it
condenses into a liquid.
The heart of a refrigerator cooling system is the compressor,
which squeezes refrigerant gas (usually freon) and pumps it
to the condenser, where it becomes a liquid, giving up heat
in the process. The condenser fan helps cool it. The
refrigerant is then forced through a thin tube, or capillary
tube, and as it escapes this restraint and is sucked back
into a gas again, absorbing some heat from the food storage
compartment while it does so. The evaporator fan distributes
the chilled air.
In a self-defrosting refrigerator/freezer model, moisture
condenses into frost on the cold evaporator coils. The
frost melts and drains away when the coils are warmed
during the defrost cycle which is initiated by a timer, and
ended by the defrost limiter, before the frozen food melts.
A small heater prevents condensation between the compartments,
the freezer thermostat turns the compressor on and off, and
the temp control limits cold air entering the fridge, by
means of an adjustable baffle.
Smoke Detectors
Is your smoke detector good at scaring to death spiders who
carelessly tiptoe inside it? Have you ever leapt out of the
shower, clad only in you-know-what, to the piercing tones of
your alarm, triggered merely by your forgetting the close the
bathroom door? Is it supposed to do this?
There are two types of smoke detectors on the market; the
photoelectric smoke detector and ionization chamber smoke
detector. The photoelectric type uses a photoelectric bulb
that shines a beam of light through a plastic maze, called a
catacomb. The light is deflected to the other end of the
maze where it hits a photoelectric cell. Any smoke impinging
on this light triggers the alarm (as do spiders and water
droplets in the air!). The ionization chamber type contains
a small radiation source, usually a man-made element called
Americium. The element produces electrically-charged air
molecules called ions, and their presence allows a small
electric current to flow in the chamber. When smoke
particles enter the chamber they attach themselves to these
ions, reducing the flow of current and triggering the alarm.
Both types are considered equally effective and may be
battery-powered or wired to the home's electrical system.
No matter which type you choose, if you don't have one
installed, put down this article and go buy one now!
And while you're signing that credit card voucher for the
new smoke detector, pause for a moment and gaze at that
other technological marvel you are probably holding in your
hand, the ball-point pen. Ever wonder why it's called a
ball-point? Because it has a ball. The first European
patents for the handy device were issued in the late 19th
century, but none of the early pens worked very well until
a Swiss inventor named Lazio Josef Biro designed the first
modern version in 1939. He called it a birome.
Commercial production was delayed by World War II, and
then in 1945, an American firm, Reynold's, introduced "the
miraculous pen which revolutionizes writing" at Gimbel's in
New York City. The new pen didn't work very well and cost a
whopping $12.50 U.S., but it was an instant success. The
Henry Ford of the ball-point industry, Marcel Bich, launched
the Bic pen in 1949, after developing the Biro design for two
years to produce a precision instrument which wrote evenly
and reliably and was cheap. By the early seventies, Bic pens
became the world's largest manufacturer of ball-point pens,
and today some two and one-half million Bic ball-points alone
are sold every day in North America.
Ink feeds by gravity through five veins in a nose cone,
usually made of brass, to a tungsten carbide ball. During the
writing process, the ball rotates, picking up a continuous
ink supply through the nose cone and transferring it to the
writing paper. The ball is a perfect sphere, which must fit
precisely into the extremely smooth nose cone socket so that
it will rotate freely yet be held tightly in place so that
there is an even ink flow. Although it sounds deceptively
simple, perhaps the most amazing thing about ball-point pens
is the ink. Why doesn't it just run out the end? Why doesn't
it dry up in the plastic cartridge? Bic describes the ink as
"exclusive, fast-drying, yet free flowing". The formula is,
of course, secret.
In the 19th century, writer and thinker Ralph Waldo Emerson
expressed a fear that perhaps we all feel to some extent, that
"things are in the saddle and ride Mankind". But with the help
of good household reference books, friendly reference
librarians, and helpful manufacturers only too willing to help
consumers understand their products, we can at least get a
rein on the technology in our homes.