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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.
