Magnetic Mixer Design

Magnetic Mixer Design

Mixer Head Maintenance

PharmAseptic has twenty years experience with magnetically coupled mixers systems and magnetic mixer bearings.
Bearings by nature are a wear part and must be inspected often and replaced when wear or damage is identified.  The alternative is to replace bearings on a consistent PM schedule in order to avoid un-planned outages or damage to the mixer as well as the vessel.

The common wear point on all bottom mounted magnetic coupled mixers using silicone carbide ceramic male posts is the axial face of the bearing at the transition point to the radial shaft.  Look for excess wear on the axial (flat) face of the bearing and especially any evidence of hair line cracks.  Of course any chips or cracks in other locations indicate that both male and female bearings should be replaced.

For mixers that use a threaded male post, the threaded part should be inspected for any wear.  These parts are prone to work loose while in operation resulting to damage to the bearing as well as the tank plate and potential failure of the bearing while in operation.

In some ways similar to metal to metal galling, the same phenomena occurs with ceramics.  By utilizing a Silicon Carbide sleeve and a Zirconium Oxide post you can reduce friction significantly and thus potential particle generation.  In addition, Zirconium Oxide has greater mechanical properties and thus can withstand higher mechanical shock than Silicon Carbide. The Zeta BMR series of mixers have an engineered tank plate and bearing design that eliminates this weak point and that provide some short duration dry running capabilities.

Zeta Biopharma has introduced another option to it’s already industry leading range of bottom and top mounted magnetically coupled mixer systems. The BMRt mixer is designed for applications that will see some instances of dry running. Incorporating a new range of stronger magnets that levitate the mixer head off of the axial face of the bearing, the Zeta BMRt mixer is capable of dry running.

PharmAseptic is the North American agent for Zeta Biopharma and the Zeta BMR, BMRT (Dry Running), bottom mounted mixer systems and the BMRf with extended shafts for bioreactors. Zeta also manufactures two top mounted magnetically coupled mixers systems – the AMRi and the larger AMRe mixers.  Please call for details.

Mechanical Specifications
Foot and TopCeramic
Material GradeEN 1.4435/ASTM 316L,Zirconium Oxide (ZrO2)
Silicon Carbide (SiC) on Request
Material requirementEN 10 272/10028-7, A479/A240 or SA479 SA240
DocumentationHeat Certificate 3.1 acc. to EN 10 204 for stainless steel parts
Conformity certificate 2.1 on ceram and o-ring
Surface finishRa≤0.5 μm on surfaces in product contact
Design Temperature[0°C to +135°C] [+32°F to +275°F]
Design Pressure[-1 bar(g) to + 7 bar(g)] [-14.5 psi to +101.5 psi]
pH range1-14
MarkingEach bearing is marked with material grade and id no
PackingEach item is sealed in vacuum plastic bag, labelled with art. number and packed in a box
Male bearing sealingEPDM or Silicone, approved acc. FDA regulation CFR 177.2600, USP Class VI
Quality AssuranceEach product is controlled and tested acc. to Zeta Biopharma quality assurance system

Call for details.