Fluid Power Uses
Whether you're an industry veteran or a neophyte, you've
probably grown accustomed to the sights and sounds of fluid
power. Every day, millions hear the familiar sound of aircraft
actuators or the hiss of assembly line cylinders.
For most of
us, those sights and sounds have become so ingrained that we
barely notice a subtle revolution around us:
Fluid power
innovation is progressing at an astonishing rate—so quickly
that some experts cite more progress in the last ten years than
in the 50 preceding years combined.
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Take
pneumatic positioning, for example. In 1980,
engineers believed it was impossible to position a
cylinder using air. Air is, after all, hundreds of times
more compressible than hydraulic oil, and its behavior is
inherently non-linear. Yet, pneumatic component
manufacturers can now repeatedly position a load to within
three thousandths of an inch.
How
is this possible? Electronics. Engineers have developed
numerical controllers that incorporate the non-linear
nature of air in their algorithms. By doing so, they've
altered century-old beliefs about the nature of their
medium. Suddenly, air can be used for positioning. As a
result, a multitude of industrial users have replaced
electric drives with precise pneumatic servo systems in
the past few years.
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Pneumatic components work smart in automated assembly
units like this one.
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In this flight simulator, Fluid Power allows for the safe and
economical testing of airborne systems.
The marriage of fluid power and electronics is also at the heart
of another dramatic change. Pumps, valves and actuators
are now considered smart. Users program acceleration and
deceleration profiles directly into actuators. They do the same
with pumps. By varying the position of a pump's swashplate with a
control signal, for example, they can vary the pump's output.
 On
assembly lines, smart pneumatic components can now
"talk" to personal computers and programmable logic
controllers through networks. They describe themselves and relay
their date of manufacture. They offer information regarding their
working status, such as calibration data, and they decide whether
they need replacement. Used with so-called fieldbuses, these
smart components offer new levels of diagnostics. In the past few
years, hundreds of automated factories have adopted this
technology.
Equally
dramatic are the changes wrought by new sealing and sound
insulation components. A decade ago, noise and leakage
were accepted phenomena. No more, though. Now, one manufacturer
makes a motor-pump so quiet that its valves are said to be
the noisiest component it makes. And leakage, in most cases, can
be eliminated. Consider, for example, the proliferation of
hydraulic components in amusement parks such as Disney World or
Universal Studios, or in Broadway musicals, such as Phantom of
the Opera. Visitors and theatergoers don't see puddles of
hydraulic oil beneath displays. Why? Because new sealing
technologies have solved the leakage problem. Those sealing
techniques are so effective that confident manufacturers have
raised the operating pressures of hydraulic pumps. Today, it's
not unusual to find pumps operating at pressures 2,000 to 3,000
psi higher than they did just a few years ago.
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Precision control, made possible with water
hydraulics, makes this robotic spaceman remarkably
realistic.
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New
sealing techniques have also returned water to the
forefront as a fluid power medium. Only a few
years ago, water was viewed as a curiosity - an outdated
technology driving creaky machinery. Now, that too is
changing. Manufacturers are dealing with leakage and
erosion problems through the use of new ceramic materials,
such as aluminum oxides and zirconias. Those materials
stand up better to higher pressures, exhibit less
permanent deformation, corrode less and wear better.
Result: manufacturers now employ water hydraulics in such
locales as meat-packing plants and pharmaceuticals
concerns.
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In
tandem with this innovation, fluid power has continued to
offer all of its traditional advantages. Hydraulics,
for example, is still unmatched when it comes to combining
sheer muscle with mobility. Yet, it also
continues to improve. Through the design of new filters
and cleanliness sampling tools, engineers have extended
the life of today's mobile hydraulic components from
months to years in some cases.
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At the National Fluid Power Association, we believe
that our industry has entered a technological renaissance. The
marriage of fluid power with electronics has rekindled our fires
of innovation. It has yielded products that are smarter,
more powerful and more precise. In some cases, it has launched
whole new technological disciplines. Right now, we are seeing
some of the most dramatic changes in the history of modern fluid
power.
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