IKA S 10 N - 5 G dispersing tool, 5 mm, 0003304000

Rotor-stator kinematics and sub-millimetre shear stress

The physical breakdown of tissues (homogenisation) or the production of highly stable emulsions on a micro-scale requires extremely high-frequency mechanical energy dissipation. The IKA S 10 N - 5 G dispersing tool operates according to the process engineering rotor-stator principle within a working volume of 0.5 to 10 ml. Driven by the T 10 basic drive at up to 30,000 revolutions per minute, the fluid is drawn hydrodynamically into the centre of the rotor and forced outwards by radial centrifugal force. The process-critical stage takes place in the gap, exactly 0.1 mm wide, between the 3.8-mm rotor and the 5-mm stator. The extremely high flow velocities occurring here (peripheral velocities of up to 6.0 m/s) generate enormous mechanical shear forces and localised hydrodynamic cavitation, which irreversibly shatter the cell membranes or droplet geometries in fractions of a millisecond.

Thermodynamic limitations and fluid friction

The application of such massive kinetic energy within a microscopic shear gap inevitably induces massive thermodynamic exothermic heat (friction heat). As the surface-to-volume ratio is extremely low in microvolumes (e.g. in Eppendorf vials), this thermal energy cannot be passively dissipated. Without external cryogenic cooling (ice bath), the matrix would boil within seconds and thermolabile analytes (such as RNA, DNA or proteins) would denature. The PTFE shaft’s plain bearing is highly chemically resistant; however, it restricts the system to wet grinding only. Dry running without a liquid matrix would mechanically destroy the tribology of the PTFE bearing due to immediate thermal overload.

Material integrity and molecular biological sterility

In PCR trace analysis or forensics, the absolute prevention of molecular cross-contamination (carry-over of foreign nucleic acids) is the paramount metrological principle. The media-contacting profile of the S 10 N - 5 G is made entirely of high-alloy, corrosion-resistant stainless steel (AISI 316L) and PTFE. This monolithic material architecture allows for thorough decontamination using aggressive solvents as well as complete thermal sterilisation in an autoclave (121 °C). To maintain hydrodynamic flow and cavitation in the long term, the microscopically fine slots in the stator must be cleaned with metrological precision to physically remove biofilms or polymerisation residues.

Technical details

Fluid mechanics & kinematics

• Processing principle: Rotor-stator shear comminution
• Operating volume range (based on H₂O): 0.5 – 10 ml
• Stator diameter: 5 mm
• Rotor diameter: 3.8 mm
• Gap width (shear zone): 0.1 mm
• Peripheral speed (max. at 30,000 rpm): approx. 6.0 m/s
• Permissible final particle size (suspensions): 5 – 25 µm
• Permissible final particle size (emulsions): 1 – 10 µm

Geometry & system limits

• Minimum/maximum immersion depth: 20 mm / 75 mm
• Shaft length (total): 92 mm
• Permissible viscosity of the medium (max.): 5,000 mPa·s
• Tribological bearing arrangement: plain bearing (wet running only permitted)

Materials Science & Thermodynamics

• Materials in contact with the medium: stainless steel (AISI 316L / 1.4404) and PTFE (polytetrafluoroethylene)
• Operating pH range: pH 2 – 13
• Thermal limitation (maximum operating temperature): 180 °C (short-term/for sterilisation)
• Autoclavability: Yes, fully thermally sterilisable (121 °C / 2 bar)
• Permitted sterilisation methods: Autoclaving, chemical, flammable (restricted due to PTFE)

Contents of delivery

• 1 x IKA S 10 N - 5 G dispersing tool

(Important note: The ULTRA-TURRAX T 10 basic / standard high-speed drive, which is essential for rotation, is not included in the scope of delivery!)

Individual requirements & accessories

The S 10 N - 5 G is purely a kinetic interface and does not generate any shear forces without the IKA T 10 basic drive system. In analytical molecular biology, the cleaning protocol for microtubes is extremely time-consuming. For high-throughput laboratories (high sample throughput), we therefore strongly recommend procuring several identical tools to avoid disrupting the analytical workflow during autoclaving cycles. Please contact our procurement service at any time for strategic requirements planning for your dispersion infrastructure.