RLS, LLC. offers its services for sealing rotary shafts of bioreactors and fermenters. We are ready to complete your process equipment with absolutely hermetic, highly reliable (a 5-year life span) and requiring NO maintenance ferrofluidic seals.

We were the first (and the only) to implement ferrofluidic technology into pharmaceutical and biomedical industry.

Our ferrofluidic systems provide absolute process sterility for at least 1000 hours of constant work both for rotating or static shaft of agitator drive. (Proved by Customers’ tests).

More than 200 of our sealing systems work on Russian bio and pharma plants, some of them for more than 7 years without any maintenance.

Magnetic Fluid Seal


Ferrofluidic seals proved their efficiency in biotechnology. They possess the unique property in comparison to other types of seals keeping the sterility at the reactor’s volume within an extremely prolonged period of time with no maintenance. Magnetic fluid seal is equally effective both at excessive pressure and rarefaction. For some processes this is the only way to follow. Magnetic fluid employment for sealing bioreactor agitator shafts is safe and FDA approved.
 Magnetic fluid seals are employed for sealing rotary shafts of bioreactors and fermenters of 0.01 – 6 m3 useful capacity.

Main parameters and features

  • Shaft diameter from 6 to 200 mm;
  • Circumferential velocity up to 10 m/s;
  • Endure multiple sterilization with superheated steam up to 150 °C and pressure drop up to 4.5 Atmo;
  • Employed for sealing rotary shafts of bioreactors/fermenters (shaft diameters: 8-70mm). Seals for larger diameters (up to 120mm) can be also designed.
  • Apart from ferrofluid seals’ production we also specialize in the design and manufacturing of seal and bearing units and hermetic spindles employing magnetic fluid seal. We also design and produce magnetic fluid seal specially adapted for counter rotating applications.

Hermetic spindle a cost-effective solution of shaft sealing to fit allshaft dimensions at one time and take advantage of all magnetic fluid seal benefits

Our experience of magnetic fluid seal integration into biotechnology enterprises leads us to an effective solution of highly convenient design of agitator shaft sealing. Hermetic spindle is a drive support that can be equipped with appropriate flanges to be mounted to the reactor and motor-reductor.

magnetic fluid seal for biotechnology

For cost-effective process equipment upgrade we designed two dimensional types of spindles. The one to fit shafts from 30 up to 50mm diameter and the second to fit shafts from 50 to 70mm diameter. This “easy-fit” design will save your time and effort and will prevent you from such failure points as mismatching components or power ratings 50-70 mm.