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Alfa Laval Culturefuge 200 Separator

Many new biological products are derived from fragile organisms. Although relatively easy to separate the trick is accomplishing the separation in a gentle manner without destroying the shear sensitive cell wall membranes that isolate the complex intracellular proteins from the extracellular target proteins. If this can be avoided, downstream purification of the target proteins becomes much easier.

The Alfa Laval Culturefuge 200 is a steam-sterilizable hermetic centrifuge designed for separation of mammalian and microbial cells as well as cell debris and suspended proteins at capacities up to 10 m3/h The unique hermetic design with bottom feed not only gives gentle acceleration of shear-sensitive particles; it also simplifies the peripheral equipment and minimizes turbulence in the feed by having control valves on the outlet. The hermetic inlet together with the special geometry of the separator leads to maximum separation efficiency. Special attention has been paid to a hygienic, CIPable design which is a pre-requisite for successful sterilization.

Application

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 pressurised steam possible.

All metal parts in contact with the process liquid are made of stainless steel with surface finish Ra <0.8 or Ra<0.5, the latterel-polished.

The bowl is of the solids-ejecting disc type with an automated hydraulic operating system for discharging. It is a so-called timer triggered discharge system, meaning that the bowl content is emptied at pre-set discharge intervals. In production normally only part of the bowl content is emptied, whereas during CIP total discharges are possible. The partial discharge takes place at full speed without any interruption of the feed. 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 (IEC or NEMA type) 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.

Design features

• Fully hermetic design for minimal shear stress and absence of oxygen.
• Different disc stacks for different sediment loading
• Two different outlet impeller diameters available
• Designed for easy cleaning-in-place (CIP).
• The centrifuge system can be made fully contained
• 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 270 kPa steam in a 20-30 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.

Working 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 sediment takes place in between the discs. The light phase moves towards the center and is discharged by an impeller (4). The heavy sediment phase is collected at the periphery and 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 (5) to drop down, thus opening the sediment ports (6) at the periphery.

Utilities consumption

Material data

Technical specification

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