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Alfa Laval Culturefuge 400 B Separator

Many new biological products are derived from fragile organisms. In high density fermentations, where the biomass loading cannot be handled by conventional intermittent (ejection), an alternative continuous discharge via a top disk and built-in impeller is realisable with this machine. Damage to the delicate cell wall is minimized thus enabling recovery of valuable solids intact. The Culturefuge 400 B is a steam-sterilizable hermetic machine designed for separation of mammalian and microbial cells as well as cell debris and suspended proteins at capacities up to 25 m3/h with continuous removal of solids. The unique hermetic design with bottom feed gives not only a gentle acceleration of shear-sensitive particles; it also avoids pick-up of oxygen. The hermetic inlet together with the special geometry of the separator leads to maximum separation efficiency. Special attention has been paid to a hygienic, CIP-able design which is a pre-requisite for successful sterilization.


The machine is designed for clarification duty, separating particles from one liquid, especially shear sensitive particles. Applications that require low oxygen pick-up can also take advantage of the hermetic features offered by this machine. The sterilizability makes the machine suitable for most biotechnological separation duties.

Standard design

The machine consists of a frame that has a horizontal drive shaft, worm gear, lubricating oil bath and a hollow vertical bowl spindle in the lower part. The bowl is mounted on top of the spindle, inside the space (bowl casing) formed by the upper part of the frame, the solids collecting cover and the frame hood. The bowl casing is double-walled for cooling and noise reduction. The bowl is sealed off from this space by mechanical seals. There is also a mechanical seal at the bottom of the spindle, and a mechanical seal at the top of the spindle to make sterilization with steam possible. All metal parts in contact with the process liquid are made of stainless steel.

The bowl is of the continuously solids-discharging disc type with an automated hydraulic operating system for CIP discharge. During CIP total or partial discharges are possible that take place at full speed. The hydraulic/pneumatic system for the discharge is mounted on the lower part of the frame.

The centrifuge is available with main connections as sanitary clamps and all other utility connections of clamp type. The electric motor is suitable for variable frequency drive, which makes it possible to have bowl speeds down to 80% of the maximum bowl speed.

The design conforms to a number of EC directives, and the machine is made in accordance with the general directives for machinery. The machine is equipped with nozzles for flushing of the bowl top, the bowl bottom and the solids collecting chute.

Operating principle

Separation takes place inside a rotating bowl. The untreated feed is introduced to the bowl from the bottom through a hollow spindle (1) and is accelerated in the distributor (2) before entering the disc stack (3). The separation of the heavy phase particles and heavy sediment takes place in between the discs. The light phase moves towards the center and is discharged by an impeller (4). The heavy phase particles leave the bowl over the top disc (5) and are taken out by another impeller (6). At CIP, contaminants and residual solids collected at the periphery is ejected from the bowl intermittently at full operating speed. The variable volume partial discharge is achieved by a hydraulic system below the separation space. At preset intervals, this system forces the sliding bowl bottom (7) to drop down, thus opening the sediment ports (8) at the periphery.

Design features

  • Designed for easy cleaning-in-place (CIP)
  • Fully hermetic design for minimal shear stress and absence of oxygen
  • Continuous removal of solids
  • Design pressure of the bowl casing 300 kPa
  • Design pressure for the cooling jacket 300 kPa for connection to centralized cooling circuit
  • Bowl casing and cooling jacket designed according to ASME or PED
  • Sterilizable (SIP) with 210 kPa steam in a 30 min cycle, including discharge system
  • Most parts in contact with the process liquids available with two alternative surface finishes
  • Product wetted parts passivated (optional)
  • All product wetted polymers and seal rings compliant with FDA regulation

Utilities consumption

Electric power max. 20 kW
Flushing liquid per discharge 0–16 l
Operating liquid 2,5 l per discharge
Steam at 210 kPa pressure 20 kg (44 lbs) per sterilization
Cooling liquid for frame parts max. 550 l/h
Cooling liquid for oil cooler max. 180 l/h
Cooling water for seals min. 280 l/h

Material data

Bowl body, hood and lock ring Stainless steel 1.4462 UNS S 31803
Frame top part and hood (ASME) Stainless steel ASME S 31603
Frame top part and hood (PED) Stainless steel 1.4404 (for pressurised equipment)
Frame bottom part Cast iron, clad with Stainless steel 1.4301 UNS S 30400
Outlet parts Stainless steel 1.4462 UNS S 31803
Gaskets and O-rings product-wetted EPDM rubber and PTFE acc. to FDA
Bowl seal ring Amid polymer 66 acc. to FDA
Seal rings in- and outlet Resin impregn. Carbon Graphite acc. to FDA
Wear ring in- and outlet FDA approved self-sintered Silicon Carbide


Inlet, heavy phase and solids outlets Clamp type, 63,5 mm
Light phase outlet Clamp type, 48,3 mm
Utilities Clamp type, various dimensions

Technical specifications

Throughput capacity max. 25 m3 /h
Solids handling capacity max. 600 l/h
Bowl volume 30 l
Sludge space volume 10 l
Discharge volume at CIP 5-17 l
Bowl speed, separation max. 5119 rpm
Bowl speed, sterilization max. 120 rpm
G-force max. 7,425
Motor speed synchronous 60Hz 1800 rpm
Installed motor power, ABB/NEMA 21/22 kW (28/30 HP)
Starting time min/max 8/10 min
Stopping time with motor brake 10 min
Feed temperature range 0–100°C
Feed inlet pressure required at inlet flange min. 200 kPa
Liquid outlet pressure at outlet flange 400-500 kPa
Sound pressure 73 dB(A)
Overhead hoist lifting capacity min. 1000 kg (2200 lbs)

Shipping data

Centrifuge weight (without motor) 1710 kg (3770 lbs)
Bowl weight 600 kg (1320 lbs)
Motor weight, ABB/NEMA 164/211 kg (362/465 lbs)
Gross weight 2150 kg (4740 lbs)
Volume 5 m3