Throughout the MGM classic, The Wizard of OZ, Dorothy, the main character, repeatedly expresses her desire to go home. Near the end of the film, she learns that she always had the ability to get home; she just didn’t realize it. The same may hold true for zero-leak hydraulics. Many believe that the technology already exists to build a zero-leak hydraulic system, while others believe it will require nothing short of a pair of ruby slippers to get there.

Back in the real world, leakage continues to be a major concern. Users cite the mess, inconvenience, unsafe conditions, and high cost of cleanup as legitimate criticisms. Machine builders take these complaints as serious reasons to specify other forms of power transmission whenever possible. This reasoning often is supported by users, many of whom are even willing to pay a premium for a system that is free of hydraulics. But perhaps the greatest concern is exhibited by manufacturers of hydraulic components, whose future could be threatened by OEMs specifying more electronmechanical systems and fewer hydraulic systems.

One of the good guys in the struggle to overcome leakage is the variety of leak-free fittings that have become available. These fittings use elastomeric sealing elements as an integral part of their design to hold leakage at bay. Further proof of progress toward reducing leakage is displayed in the trend toward hydraulic integrated circuits (HICs). HICs fight leakage by dramatically reducing the number of potential leak points. This is accomplished by replacing line-mounted valves, fittings, and fluid conductors with screw-in or slip-in cartridge valves that mount into a predrilled manifold containing internal flow passages.

These and other techniques-such as mounting the hydraulic pump submerged in hydraulic fluid inside the reservoir-have been available for years. However, many OEMs and users continue to be reluctant to adopt them.

If so, the day may come when the detriments of leakage become so expensive that OEMs and users will be forced to spend a lot of money quickly to play catch-up in adopting no-leak programs.

But beyond these established methods of reducing leakage, what other techniques can be used? As progress is made, how will the hydraulic systems of the future differ from those of today? To find answers to these questions and more, Phil Swisher, director of venture development, Vickers, Inc., Maumee, Ohio, volunteered to participate in an interview with the author. Swisher is responsible for zero-leak technology research and development at the Vickers Advanced Technology Center in Rochester Hills, Mich.

H&P: Hydraulic leakage has been a topic of discussion for years. What makes current zero-leak programs any different?

Swisher: You have started with the most fundamental and critical question that can be asked. One of the unspoken-or for that matter not even thought about-strengths of any hydraulic system has been its ability to continue performing normally even when it leaks. In the not-so-distant past, if the choice was between stopping production to fix a leak that was lowering the reservoir fluid level of adding fluid while letting production continue, adding fluid was the answer.

A colleague of mine puts it in perspective when he says, "If an occasional spark (an electrical leak) is seen coming from an electric drive of control, things are shut down in a hurry!" Hydraulic leaks have not been treated with the same sense of urgency. Those days are gone for the savvy user!

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