Enhance uptime and yield with Alfa Laval tank mixers designed for hygienic and aseptic applications. Our patented technology guarantees efficient and uniform mixing of powders, liquids, and gases while minimizing the total cost of ownership. These tank mixers, known for their compactness, energy efficiency, and ease of maintenance, bolster process flexibility, effortlessly blending a range of product formulations with varying viscosities, densities, and volumes.

Hygienic tank mixers fall into two main engineering patterns: fluid-driven rotary jet mixers and magnetically coupled levitating-impeller mixers. Each pattern suits different process constraints: pressure-limited recirculation loops and automatic tank cleaning favour rotary jets, while strict aseptic piping, low-shear residence, and full drainability favour magnetic levitation systems.

Rotary Jet Mixer overview

Rotary Jet Mixers from Alfa Laval are media-driven, self-lubricating tank mixers that accept recirculated process fluid as the motive energy. Fluid passes through a turbine; that turbine transmits torque into a gearbox that produces a combined horizontal rotation of the mixer body and vertical rotation of the nozzles. The indexed jet pattern progressively covers the tank surface; four-nozzle units reach a full mixing pattern after 45 hub revolutions (43 body revolutions). Typical working pressures across IM models range up to 12 bar; the IM 10 is specified for lower ranges (3–8 bar). These machines double as automatic tank cleaning devices when the vessel is empty, because the same jet pattern used for mixing provides high-coverage cleaning.

LeviMag and LeviMag UltraPure overview

The LeviMag family uses an external drive unit and a magnetic coupling that drives and axially lifts the internal impeller. Because the impeller is levitating, there is no product-penetrating shaft seal and axial wear is minimised. Standard LeviMag impellers and weld plates are AISI 316L and have mechanically polished finishes (Ra < 0.8 µm). The UltraPure version adds electropolishing to reach Ra < 0.38 µm for the wetted surfaces used in sterile pharmaceutical processes. Working pressure for LeviMag units is −1 to 7 bar(g), and five impeller sizes (100–300 mm) cover volumes from a few tens of litres up to 40,000 litres depending on duty and viscosity.

Hygienic tank mixers are used across food, beverage, dairy, pharmaceutical, biotech and cosmetics processing. Each sector imposes different priorities: thermal tolerance and rapid CIP for dairy; low shear and traceable materials for pharma; sterile surface finish and certification for biotech; and viscous blending capability for cosmetics. Below is a compact table summarising typical industry fits and the key design requirement for each.

Where a rotary jet mixer fits in a process line

Rotary Jet Mixers are typically installed as an in-tank device connected to an external recirculation loop. A pump draws liquid from the vessel, passes it through a filter and any dosing or instrumentation, then returns it to the tank via the mixer. Inside the mixer, the turbine converts the recirculated flow into an indexed jet pattern; higher recirculation flow rates increase mixing intensity. This layout is common where the process already has a recirculation loop (CIP systems, heat-exchange loops) and where automatic tank cleaning is also desired.

Where a LeviMag fits in a process line

The LeviMag is a direct-in-tank magnetic mixer: the external drive unit is mounted to a weld plate and the impeller sits in the product zone. It is suited to aseptic tanks and processes that prioritise product containment and traceable material certificates. LeviMag units are used where eliminating any shaft seal is valuable for sterility validation and where the ability to run dry during drainage and CIP (below 50 RPM) is beneficial. For pharma and biotech, documentation options such as Alfa Laval Q-doc (including EN 10204 3.1 MTRs and FDA compliance statements for non-metallics) are often required and available.

ATEX and hazardous atmospheres

Tanks that contain flammable solvents, alcohols or produce combustible mists may be ATEX-classified. Alfa Laval offers ATEX/IECEx variants for both families. IM-series machines (IM 15, IM 20, IM 25) are available as certified Category 1 components for installation inside the tank (Zone 0/20) under Directive 2014/34/EU; when used in a hazardous area they must be fully filled with the cleaning/mixing fluid during operation. LeviMag ATEX variants and the associated protective measures require submerged operation, level-switch monitoring and frequency-converter arrangements in line with EN ISO 80079-37 and EN 60079 standards; refer to the product manuals for the EPL and monitoring requirements.

Choosing by requirement

Choose a rotary-jet mixer where you already have or plan a high-flow recirculation loop, want integrated tank cleaning performance, and expect to operate at pressures up to 12 bar for effective jet reach. Choose a LeviMag where eliminating a shaft seal and providing documented aseptic surfaces are top priorities, or when low-shear blending and full drainability are essential. If your process requires electropolished wetted surfaces (Ra < 0.38 µm), the LeviMag UltraPure is the targeted option.

Indexed rotary-jet mixing: components and principle

A rotary-jet mixer converts recirculated liquid into powerful directional jets that sweep the interior of the tank in a controlled, indexed pattern. Key components are the turbine (driven by the recirculated flow), a gearbox that converts turbine torque to combined body and nozzle motion, a hub carrying the nozzles, and precision nozzles sized for the duty. The turbine speed increases with flow; nozzle diameter and inlet pressure set the jet energy and reach. The indexed interaction of body rotation and nozzle rotation lays a repeatable pattern across the tank surface, eliminating dead zones. Alfa Laval manuals document that four-nozzle machines establish a full pattern after 45 hub revolutions — that figure guides engineers when estimating cycle times for full coverage.

Magnetic levitation mixing: components and principle

LeviMag mixers use a magnetic coupling between an external drive rotor and an internal impeller. The drive rotor and the impeller have permanent magnets; when the rotor turns it drags the impeller. The magnetic field also supplies axial lift that raises the impeller off the male bearing into a levitation gap. This removes a product-penetrating shaft or mechanical seal from the design. Major components are the weld plate, male and female bearings (zirconia and silicium carbide in standard configurations), the impeller with radial blades, and the external drive unit housing the motor and gearbox. Because there is no shaft seal, the product zone is physically isolated from the motor and gearbox components.

Key selection factors

When selecting a tank mixer, evaluate the following in order: process duty, tank geometry, viscosity, required CIP/SIP temperatures, available utilities, and regulatory documentation needs.

1. Process duty and viscosity

Define the primary duty: keep homogeneous (low energy), mild blending, mixing (short mixing time) or heavy-duty dissolution of solids. LeviMag selection charts map net tank volume and viscosity against impeller diameter for four duty levels; they assume specific preconditions such as liquid height ≤ 2.5× tank diameter and specific gravity ≤ 1.1. For Rotary Jet Mixers, nozzle diameter, inlet pressure and volumetric flow determine jet reach; published performance curves assume a 1 cP fluid and show reduced reach as viscosity rises, so account conservatively for non-Newtonian or thicker fluids.

2. Tank geometry and placement

Both families must be positioned to avoid mechanical contact with tank internals. Rotary Jet Mixers should be centred in the liquid and placed to the depths stated in the product manuals (IM 10 minimum 200 mm below surface; larger IM models typically ½ m below surface). LeviMag impellers have specific levitation and run-out tolerances; the weld plate must be installed and inspected to avoid distortion during welding, and total run-out of the magnetic drive rotor must be kept below 0.2 mm.

3. Temperature, CIP and SIP

Confirm maximum operating media temperature and cleaning/sterilisation needs. LeviMag units are rated for product mixing up to 90 °C, CIP up to 95 °C at ≤50 RPM, SIP up to 150 °C at 0 RPM and 125 °C at low RPM. Rotary Jet Mixers have model-dependent limits: several IM models are rated to 120 °C working temperature and 140 °C max temperature/steam; IM25 has a lower working temperature specification in its manual. Ensure the mixer chosen matches the CIP/SIP profile and bearing/seal material compatibility.

4. Materials and surface finish

Specify wetted materials (AISI 316L is common) and surface finish for sanitary or aseptic validation. LeviMag UltraPure is electropolished to Ra < 0.38 µm; standard LeviMag is mechanically polished to Ra < 0.8 µm. For Pharma/biotech, request EN 10204 3.1 material certificates and other documentation tiers such as Alfa Laval Q-doc when required.

5. Utilities and controls

Rotary Jet Mixers require a recirculation pump and properly sized supply lines and filters (a 3 mm filter is a common recommendation to protect the turbine and gearbox). LeviMag drive units require a frequency converter: the IE5 IPMSM motor must be operated via a converter and must not be connected directly to mains. Verify voltage selection rules (230 V versions for 3×200–240 V grids; 400 V versions for 3×380 V and above) and ensure the converter is sized per motor nameplate data.

Selection reference table

Maintenance and service notes

Follow manufacturer service intervals and use genuine spare kits. LeviMag recommends O-ring changes annually and bearing replacement around 20,000 hours; Rotary Jet Mixer service intervals are model-specific (many IM models reference 4,000-hour service checks and published wear limits for slide bearings and collar bushes). Where ATEX versions are used, service must follow Alfa Laval’s instructions and authorised service centres to preserve certification.