Optimize your mixing processes with Alfa Laval tank agitators. Achieve maximum mixing efficiency, ideal flow rates, and gentle product treatment. Our versatile, customizable designs and mounting options allow precise tailoring to your unique hygienic mixing needs. Elevate quality and performance while lowering energy and maintenance costs. Explore our purpose-built agitators for a comprehensive solution. Upgrade your tank mixing with Alfa Laval and unlock the potential for improved quality and cost savings

Top-mounted agitators: ALT and ALTB

The Alfa Laval ALT is a top-mounted agitator with a free-hanging shaft. It suits atmospheric and pressurised tanks across dairy, food, beverage, and pharmaceutical production. The drive unit accepts an optional stainless steel bearing frame, and the shaft carries one or more EnSaFoil impellers. An ATEX-certified version is available for potentially explosive environments. Surface finishes are available to Ra < 0.51 µm for UltraPure duties.

The ALTB variant adds a bottom steady bearing with PEEK wear bushings that support the shaft inside the tank. This extends service life and reduces radial deflection on long shafts. The ALTB operates at pressures from full vacuum to 10 bar, with CIP temperatures to 95 °C and SIP to 150 °C. Bottom bearing bushings can be replaced without dismantling the drive. This model is particularly suitable for tall vessels where a top-mounted mixer requires additional stability.

Bottom-mounted agitators: ALB and EnSaLine B

Bottom-mounted configurations place the drive below the tank, sending the shaft upward through a floor-level seal housing. The ALB is a modular industrial agitator whose drive, seal arrangement, shaft, and impeller are each independently configurable. It uses bellow or non-bellow mechanical seals in single or double arrangements, with a double seal option for high-pressure and aseptic duties. Standard shaft diameters and bearing frame sizes are specific to the application torque.

The EnSaLine B advances this concept with a dedicated cartridge shaft seal that packages all seals and bearings into one replaceable unit. Inside the tank, the fully flush design eliminates the mounting flange entirely, and the hygienic seal housing leaves no crevices for product accumulation. One technician can complete a full service in under 30 minutes, tool-free. The shaft stays fixed during maintenance. EnSaLine B is prepared for wireless condition monitoring and operates from −10 °C to 95 °C at pressures from −1 to 6 bar.

Side-mounted agitators: ALS and EnSaLine S

A side entry agitator enters the tank through the cylindrical wall rather than the top or bottom head. The ALS provides the same modular configurability as the ALB, with right-angle, coaxial, parallel-shaft, or direct-drive gearbox options. It supports ATEX certification and Q-doc documentation packages. The ALS handles a wide range of duties from dairy storage to brewery fermentation.

The EnSaLine S mirrors the EnSaLine B's cartridge seal architecture in a side-mounted format, delivering the same tool-free access, under-30-minute service, and fully flushable interior. Retrofit welding flanges are available to upgrade existing side-mounted installations without replacing the tank nozzle. Both side-mounted models handle the same industry range and duty types as their bottom-mounted counterparts, including heat-transfer circulation through dimple-jacket tanks.

Top-mounted agitators: ALT and ALTB

The Alfa Laval ALT is a top-mounted agitator with a free-hanging shaft. It suits atmospheric and pressurised tanks across dairy, food, beverage, and pharmaceutical production. The drive unit accepts an optional stainless steel bearing frame, and the shaft carries one or more EnSaFoil impellers. An ATEX-certified version is available for potentially explosive environments. Surface finishes are available to Ra < 0.51 µm for UltraPure duties.

The ALTB variant adds a bottom steady bearing with PEEK wear bushings that support the shaft inside the tank. This extends service life and reduces radial deflection on long shafts. The ALTB operates at pressures from full vacuum to 10 bar, with CIP temperatures to 95 °C and SIP to 150 °C. Bottom bearing bushings can be replaced without dismantling the drive. This model is particularly suitable for tall vessels where a top-mounted mixer requires additional stability.

Bottom-mounted agitators: ALB and EnSaLine B

Bottom-mounted configurations place the drive below the tank, sending the shaft upward through a floor-level seal housing. The ALB is a modular industrial agitator whose drive, seal arrangement, shaft, and impeller are each independently configurable. It uses bellow or non-bellow mechanical seals in single or double arrangements, with a double seal option for high-pressure and aseptic duties. Standard shaft diameters and bearing frame sizes are specific to the application torque.

The EnSaLine B advances this concept with a dedicated cartridge shaft seal that packages all seals and bearings into one replaceable unit. Inside the tank, the fully flush design eliminates the mounting flange entirely, and the hygienic seal housing leaves no crevices for product accumulation. One technician can complete a full service in under 30 minutes, tool-free. The shaft stays fixed during maintenance. EnSaLine B is prepared for wireless condition monitoring and operates from −10 °C to 95 °C at pressures from −1 to 6 bar.

Side-mounted agitators: ALS and EnSaLine S

A side entry agitator enters the tank through the cylindrical wall rather than the top or bottom head. The ALS provides the same modular configurability as the ALB, with right-angle, coaxial, parallel-shaft, or direct-drive gearbox options. It supports ATEX certification and Q-doc documentation packages. The ALS handles a wide range of duties from dairy storage to brewery fermentation.

The EnSaLine S mirrors the EnSaLine B's cartridge seal architecture in a side-mounted format, delivering the same tool-free access, under-30-minute service, and fully flushable interior. Retrofit welding flanges are available to upgrade existing side-mounted installations without replacing the tank nozzle. Both side-mounted models handle the same industry range and duty types as their bottom-mounted counterparts, including heat-transfer circulation through dimple-jacket tanks.

Dairy processing

Milk storage tanks, cream tanks, and mixed-product vessels require continuous low-shear agitation to prevent fat separation and protein sedimentation without damaging the colloid structure. A tank agitator with EnSaFoil impellers generates high axial flow that keeps the entire tank volume homogeneous at minimal energy input. CIP compatibility is non-negotiable: the agitator interior must be fully cleanable in place, with no dead zones or shadow areas between blades. EHEDG-certified designs meet this standard, specifically for storage and UHT products.

Food and beverage

Powder protein and oil dispersions, micro-salt blending, syrup dissolution, and juice tanks with fruit particles all fall within the mixing agitator's operating envelope. Particle-laden fluids demand gentle suspension without crushing solids. Crystallisation tanks need controlled agitation rates to manage nucleation. Beverage and brewery applications add the requirement for dimple-jacket circulation, where the agitator moves media past the heated or cooled tank wall (surface dents) to accelerate thermal exchange.

Personal care and cosmetics

Lotions, shampoos, and cream formulations rely on consistent emulsification and dispersion. Surface finish matters here because residual product films affect batch-to-batch consistency and extend cleaning cycles. Hygienic polished finishes at Ra < 0.8 µm are standard; higher-purity applications may specify UltraPure Ra < 0.51 µm or electropolished Ra < 0.38 µm finishes to ensure product safety.

Pharmaceutical and biotechnology

A pharmaceutical agitator for sterile or aseptic tanks must support SIP at temperatures up to 150 °C, operate under pressures up to 10 bar (for the ALTB/ALT range), and present an electropolished surface finish of Ra < 0.38 µm to prevent biofilm formation. Double mechanical seals with flush media capability isolate the process from the external environment. The EnSaLine B, EnSaLine S, ALT, ALB, and ALS all offer UltraPure options on product-wetted parts and comply with EHEDG, FDA, USDA, and 3-A Sanitary Standards.

Wastewater treatment

Flocculation tanks for wastewater treatment represent the industrial end of the spectrum. Here, industrial shot-peened surface finishes (Ra < 3.2 µm) are acceptable, and the focus shifts to drive efficiency and long bearing life rather than aseptic-grade cleanability. Standard AISI 304 is often used for non-wetted external parts like the gear motor or stainless steel shroud.

Axial-flow impeller mechanics and EnSaFoil design

An electric drive motor transmits torque to the agitator shaft either directly or through a gearbox. The shaft rotates the EnSaFoil impellers, whose blade profile produces a strong axial pumping action directed along the shaft axis. Liquid is drawn from one end of the vessel and pushed toward the opposite end, creating a large-scale circulation loop that blends the full tank volume with minimal radial turbulence. This axial pump effect is highly effective at keeping media homogeneous with low shear stress.

Choosing between two-blade and three-blade variants depends on the required pumping capacity. Axial impellers move a large volume of fluid per revolution at comparatively low tip speeds. Lower tip speed reduces the shear rate experienced by the product, protecting structural integrity. EnSaFoil impellers are available from 125 mm to 1,900 mm in diameter. Matching impeller diameter and rotational speed to the specific tank geometry and product properties determines the overall energy consumption and mixing effectiveness.

Seal housing and hygienic protection

Where the shaft enters the tank, a seal housing prevents leakage and contamination. Seal arrangements fall into several categories. Single mechanical seals, available as bellow (S1) or non-bellow (S2) types, suit many atmospheric duties. Double mechanical seals (D) handle high-pressure applications and aseptic processes, using a lantern spacer and a flush chamber between the two seal faces. These faces typically use carbon or silicon carbide pairings.

The EnSaLine B and EnSaLine S utilize a cartridge shaft seal that groups all seals, O-rings, and bearings into one removable module. No mounting flange protrudes into the tank, and the seal housing interior is fully flushable. During pharmaceutical operation, flush media temperatures can reach 140 °C, while SIP sterilisation of the housing is rated to 150 °C. This design allows for tool-free replacement from outside the tank, significantly reducing maintenance window requirements compared to traditional modular designs.

Selection criteria for process tanks

Selecting the correct agitator requires defining several process parameters. The primary hardware decision begins with mounting location: top-mounted (ALT, ALTB), bottom-mounted (ALB, EnSaLine B), or side-mounted (ALS, EnSaLine S). This is often dictated by tank access, headroom, and cleaning accessibility.

Operating data and materials. Standard operating temperatures range from −10 °C to 95 °C, but SIP cycles reach 150 °C. Pressure requirements vary by configuration; for example, the ALTB handles up to 10 bar, while the EnSaLine B is rated for −1 to 6 bar. Product-wetted parts are AISI 316L (standard), with seal elastomers in EPDM, FKM, or FFKM depending on chemical and thermal requirements. Surface finish must be matched to industry standards: Ra < 3.2 µm for industrial use, Ra < 0.8 µm for food/hygienic, and Ra < 0.51 µm or better for UltraPure duties.

Motor and drive assembly. Standard motors are IEC-rated with IP55 protection (IP66 optional) and IE3 efficiency (IE4 optional). Gearbox configurations include right-angle, coaxial, parallel-shaft, and direct-drive. These are standardly painted RAL5010 or can be shrouded in stainless steel for food-grade environments. All motor voltages and frequencies (50Hz and 60Hz) are available to match local power grids.

Agitator vs mixer: selecting by shear requirement

The agitator vs mixer distinction centres on shear profile. A tank agitator with EnSaFoil impellers moves the entire tank contents through a large-scale circulation loop. Shear is deliberately minimised to handle sensitive dairy or fruit products. A high-shear mixer concentrates energy in a small zone to break down droplets or particles. These technologies are often complementary; a mixer handles initial powder wetting, while the agitator maintains homogeneity in the storage tank. Selection is critical: an agitator cannot effectively emulsify, and a high-shear mixer cannot efficiently maintain bulk homogeneity in large storage vessels.