Magnetic Fluid Seal Technology
Magnetic fluid seal technology is developed based on magnetic fluid. After being injected into the gap with magnetic field, the fluid fills the entire area and forms a liquid O-ring sealing structure. The magnetic fluid vacuum rotary feedthrough is a dedicated device for rotary motion transmission of vacuum vessels. It consists of permanent magnetic field, magnetic poles, magnetic multi-pole drive shaft and magnetic fluid. Each annular gap is filled with magnetic fluid. Under ideal working conditions, magnetic fluid forms multi-stage magnetic fluid sealing structures between pole pieces. A single stage can withstand 0.15~0.2 atm, and the total pressure resistance of the device is the sum of all stages. For vacuum environment adaptation, the standard design pressure resistance exceeds 2 atm with high safety redundancy.
Magnetic Fluid Applications
At present, magnetic fluid feedthroughs have been widely applied in various precision feed control equipment, covering key processes such as silicon crystal growth, electronic target positioning, sputtering, plasma etching, chemical vapor deposition, ion implantation and LCD refurbishment. Its sealing technology can effectively isolate and protect robots from harmful external media, significantly reduce unplanned downtime, provide critical support for large-scale continuous production in high-end manufacturing, and deliver outstanding application value.
Magnetic Fluid Characteristics
Sealing Performance: Magnetic fluid fully wraps the rotating shaft circumferentially to achieve complete barrier against gas, liquid and aerosol. Leak rate ≤1×10⁻¹¹ Torr·L/sec, reaching the detection limit of mass spectrometer for near-zero leakage.
Service Life: Liquid O-ring sealing structure centered on high-stability magnetic fluid. The device achieves maintenance-free operation with MTBF ≥10 years.
Operational Reliability: Coupled design of permanent magnetic circuit and magnetic fluid. No mechanical contact on sealing pairs; only normal wear occurs on bearings.
Cleanliness: Contact-free and wear-free design generates no particles, reducing particulate contamination of the system at the source. Compatible with low-pressure environment, easy maintenance, vacuum level controllable down to 10⁻⁸ Torr.
Torque Transmission: 100% lossless torque transmission, ensuring unidirectional motion of drive shaft without additional resistance or jamming.
Dynamic Performance: Magnetic fluid features low viscous resistance. Combined with non-contact design of feedthrough and sealing pairs, the device operates stably at high rotational speed with low damping.
