Laboratory membrane testing

HexaMem Stirred Cell

A compact and versatile test cell for laboratory-scale membrane trials with polymeric and ceramic flat-sheet membranes.

HexaMem supports experiments in microfiltration, ultrafiltration, nanofiltration, and reverse osmosis. It is designed for reproducible membrane screening, process development, and controlled investigation of flux, retention, concentration polarization, and fouling behavior.

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Functional Principle

HexaMem consists of two main components: a magnetic stirrer drive unit and a hexagonal filtration cell. A circular flat-sheet membrane is installed securely over an O-ring seal, enabling fast membrane changes and reliable leak-tight operation.

During operation, a magnetically driven stirrer generates controlled tangential flow across the membrane surface. This defined crossflow helps reduce concentration polarization, minimize fouling, improve mass transfer, and simulate realistic crossflow membrane processes.

Key Advantages

Controlled Crossflow

The magnetic rotor is driven by a programmable stepper motor, allowing defined speed profiles, ramps, and complex flow patterns.

Product-Specific Stirrer Geometry

Stirrer geometry can be adapted to the product, taking viscosity, rheological behavior, and shear sensitivity into account.

Improved Mixing Dynamics

The hexagonal cell shape prevents simple co-rotation of the liquid and promotes effective mixing and mass transfer at the membrane surface.

Operating Modes

Operation with Pump

A pump transfers liquid from a feed vessel into the test cell under controlled pressure. A fine control valve sets the backpressure, while rotor speed controls crossflow independently of pump pressure. Permeate can be collected on a balance for continuous flux and concentration-factor calculations.

Operation with Pressurized Gas

Instead of a pump, inert gas can be used to generate operating pressure. A pressure regulator controls the gas supply to a pressure-resistant feed vessel. This setup is suitable for batch operation and controlled laboratory filtration trials.

Applications

Membrane Screening

Compare flat-sheet membranes under reproducible hydrodynamic conditions.

Small-Batch Production

Produce small sample quantities for analytics, validation, and product testing.

Cleaning Trials

Evaluate membrane cleaning behavior and analyze fouling, deposits, or membrane damage.

Enzyme Membrane Reactors

Support homogeneous, gentle mixing with enhanced contact between enzymes and substrates.

Compatible Membranes

HexaMem is suitable for a wide range of flat-sheet membranes, including MF, UF, NF, and RO membranes from suppliers such as Alfa Laval, Synder, and Unisol.

Typical membrane options include PES, PVDF, PAN, regenerated cellulose acetate, polypropylene-supported membranes, thin-film composites, and polyamide RO/NF membranes.