In sterile processing the greatest threat to the batch comes from outside. A mechanical seal is a moving barrier: it wears, it needs barrier fluid, and it remains a managed risk. The BMA removes that risk by replacing the shaft entry with a hermetic magnetic coupling — a closed system that is physically incapable of leaking. Scalable from a 2-litre pilot vessel to a 150,000-litre tank.
Operating principle
Between product space and drive there is no shaft, but a magnetic field. What does not pass through the vessel wall cannot leak. The shaft seal disappears as a weak point — and with it barrier fluid, monitoring and replacement.
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Advantages
Internal destructive testing has shown the bearing system withstands over 100 minutes of dry running before seizure. Dry running is outside normal operation — but this reserve protects the machine against accidental start-up or a drainage error.
The zirconia and silicon carbide bearing surfaces are engineered for long service life. The outer bearing nevertheless stays accessible and can be replaced on site — the agitator stays serviceable as long as the vessel.
The optional speed sensor picks up a magnet in the impeller via a Hall sensor. What is measured is actual rotation inside the vessel, not motor rotation — the control system receives verified feedback, not a picture of the drive side.
The bearing materials are solid, not surface-coated. A coating can detach and shed particles; an independent study of the zirconia on silicon carbide pairing found no measurable particulate generation.
The gap between drive magnet and impeller is deliberately widened so that enough flow remains behind the impeller for cleaning. That costs magnetic force — recovered through higher-grade magnet materials rather than by narrowing the gap.
During sterilisation the machine breathes thermally. So that no unsterile voids form, the thermal expansion of the zirconia bushes is matched to that of the stainless steel housing. This allows tight fits that stay closed across the whole temperature cycle.
We manufacture ourselves and control the chain. Non-standard shaft lengths or flange adaptations are design parameters to us, not obstacles — the custom solution arrives with the reliability of a standard product.
Flange integration
The interface between vessel and agitator decides not only containment, but who can reach the bearing. Three versions that make entering the vessel unnecessary.
The default for maximum containment: the can is welded directly into the vessel bottom.
For vessels too small to enter or too large to enter safely. The can is removable and the bearing serviced entirely from outside.
A fully removable flange assembly. The entire agitator can be withdrawn downward without opening the vessel top.
Technical data
Drive
Beyond the standard AC motor we supply the type that suits the existing infrastructure.
Where compressed air is the available power source or explosion protection requires it.
For pilot plants and portable skids, where efficiency counts.
Stainless steel encapsulated, for cleanrooms and ultra-pure areas.
Closed-loop, for highest accuracy and free motion profiles.
Materials
For product contact, 1.4435 BN2 (AISI 316L) is the standard, supplied ground and electropolished to Ra < 0.4 µm on request. For aggressive media we manufacture in 2.4602, 1.4539 (904L) and duplex among others. If the process chemistry demands it, we build it.
Contact
We determine sizing, frame size and connection from your vessel. Tell us what is being mixed and in what volume.
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