The Engineering Foundation of Ferrofluid Seals
The technology underpinning modern ferrofluid rotary feedthroughs was pioneered in the 1970s, when engineers developed a revolutionary approach to dynamic, hermetic sealing for rotating mechanisms. This innovation centered on using ferrofluid to create a liquid O-ring around a rotating shaft, a concept that quickly became the industry standard for demanding precision applications. For over forty years, engineering teams have continued to refine this core technology, optimizing it for increasingly complex environments, including cryogenic systems.
Hermetic Performance Under Extreme Conditions
In cryogenic applications such as infrared cooling platforms and thermal vacuum simulators, maintaining a perfect seal is paramount. The ferrofluid rotary vacuum seal provides a hermetic atmospheric to high vacuum seal under both static and dynamic conditions, protecting sensitive environments from gas, vapor, and contaminants. According to industry specifications, the leakage rate for these seals is an exceptional 1 x 10⁻⁹ std. cc/sec, with all units being helium leak checked using a mass spectrometer. This level of zero-leakage integrity is critical for the stable operation of cryogenic cooling systems and space simulation chambers where even minute contamination can compromise results.
Mechanism and Pressure Capacity
The sealing action is achieved by trapping a low vapor pressure magnetic fluid in small annular gaps of intense magnetic fields generated by a magnetic circuit. The fluid forms multiple rings, or stages, contained in grooves machined into the components. A pressure differential can be maintained across each stage under both static and dynamic conditions. Typically, a single stage can sustain a pressure differential of 200 mbar, and the total pressure capacity of the feedthrough is approximately equal to the sum of the pressure capacities of each individual stage. This multi-stage, contact-free design ensures there is no mechanical wear on the seal itself, contributing to a long service life essential for rigorous testing platforms.
Enabling Advanced Cryogenic Applications
This unique capability for transmitting mechanical power into a vacuum chamber with zero leakage is indispensable for cryogenic systems. It enables precise rotation within infrared cryogenic platforms for sensor calibration, facilitates motion in thermal vacuum simulators for component testing, and supports mechanical functions in cryogenic cooling systems. The availability of feedthroughs with various mounting options, including ConFlat (CF) flanges designed for ultra-high vacuum (UHV) environments, makes them directly suitable for the most demanding space simulation and research applications. The technology's reliability and longevity directly support the extended operational cycles required in these fields.
We provide a range of single axle ferrofluid feedthroughs designed to meet the exacting demands of modern cryogenic and vacuum research environments.