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:

  • pumps are growing more powerful;
  • valves are smarter;
  • actuators are more precise.

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.

Take pneumatic positioning, for example. In the past, 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.

Pneumatic components work smart in automated assembly units like this one.

motion simulator

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.

Precision control, made possible with water hydraulics, makes this robotic spaceman remarkably realistic.

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.

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.

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.