Smart seals: Radial shaft seals

Dec. 1, 2007
Conventional shaft seals are designed to last a certain length of time perhaps 5,000 to 20,000 service hours before the effects of wear begin to emerge.

Conventional shaft seals are designed to last a certain length of time — perhaps 5,000 to 20,000 service hours — before the effects of wear begin to emerge. To avoid the possibility of an unexpected failure and subsequent leakage, however, most companies change out seals at regular intervals, regardless of their condition. A new seal with a built-in sensor that detects oil, plus a wicking element that laps it up in case it escapes, makes premature replacement a thing of the past, extending service life as much as 50%.

Intelligent seals that call for attention when they need to be replaced are especially helpful where extreme loads and duty cycles are involved; for example, on a bearing assembly mounted in a wind turbine or a gearbox buried in the middle of a chemical plant. Here, sensor-equipped seals make remote monitoring and diagnostics relatively easy.

Although letting seals run until failure is counterintuitive to prevailing maintenance philosophy, the new seal is destined to change some minds because it's designed to not only monitor leaks, but manage them as well. Leaking oil is captured in a repository and soaked up by a special non-woven fabric. The integrated sensor detects fabric contamination electronically as well as optically, emitting a warning signal at any saturation level the user desires as set in software. An outer sealing lip keeps the oil within the repository, preventing leakage or egress beyond the seal.


On display: Intelligent radial shaft seal

Key features: Integrated sensor detects oil absorbed by wicking element.

What it means to you: Longer service cycles and an end to preventative maintenance.

What else: Operates to 212° F; custom units available for higher temperatures and protection against water penetration.

Innovator: Simrit, a division of Freudenberg and NOK

Plymouth, Mich.

For more info: or (866) 274-6748

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