APD II (second generation) Automatic Piston Discharge Centrifuge
The most advanced centrifuge for bioprocess industry
The patented APD (Automatic Piston Discharge) (first generation) centrifuge is used for separating liquid phases and solids from each other. APD centrifuge is suitable for a broad range of two-phase solid-liquid separation applications common to the bioprocess and pharmaceutical R&D and industries.
The patent pending APD II (second generation) leverages the first generation of APD technology, is the most advanced centrifuge technology today. APD II is a breakthrough that allows the most powerful separation yet is gentle to the product in a complete automatic fashion. APD II provides solutions for high-throughput continuous flow and batch processing applications for consistent results in areas of vaccine manufacturing, antibody manufacturing, mammalian and microbial processing and blood plasma fractionation.
Principles of Operation
The centrifuge typically operates cycle by cycle continuously until all the biomaterial is processed. Each cycle normally consists 3 steps: separation-drain-discharge, or programmed otherwise according to the user’s preference.
The feed liquid enters from the top to the pre-filled centrifuge bowl which has accelerated to the desired rotational speed. Pre-filling the centrifuge is an important step to form “no air” environment to exclude foaming. The feed travels down the center core through the pull rod to the shuttle valve. At the shuttle valve, the feed then enters the bowl through accelerator channels. In the fast spinning bowl, the feed tracks up along the outer wall of the center core tube where it is clarified. The entrained solid particles are deposited on the bowl wall as the clarified centrate exits out of the bowl through the centrate outlet piping to the user’s centrate tank/receiver. Once the system determines the solids are full to the user’s pre-programmed occupancy, the centrifuge stops. After draining the remaining liquid back to the feed tank, the discharge piston is actuated to assist depositing solids to the solids vessel (The piston can be optionally used to discharge shear sensitive materials, i.e., mammalian cells.). The discharge piston completely discharges the solids as it strokes the full length of the bowl.
Central Core Tube and Shuttle Valve
The central core tube is the center of the pull rod which is integral to the shuttle valve. The narrow center core tube bears very low G force due to its small radius. This minimizes the shear stress to the feed before it enters the fast spinning centrifuge. Through the accelerator channels the feed gets fully angular - accelerated and then tracks along the outer wall of the center core tube all the way to the top. The solids get separated during the travel. The centrifuge also incorporates a zero dead space design for the feed path. This allows the feed to get fully accelerated in a gentle and "embedded" manner without contacting any air, crucial in eliminating foaming thus the shear stress to the process.
This sedimentation process continues until the bowl is considered “full” as programmed by the user. This could be 25% to 98% of the bowl volume occupied by separated solids. For most applications, the discharge piston is used to discharge the solids to be collected or discarded. The pneumatic pressure driven discharge piston can achieve TOTAL sedimented solids recovery automatically. For some applications, e.g., to collect shear sensitive whole cells, the piston is not used and the discharge is assisted by air/gas to avoid piston crushing the cells.
How It Works
- Each cycle consists: Fill (1)- separation (2)-drain (3)-discharge (4&5)
- Cycle repeats continuously until all the biomaterial is processed
- Automatic collection of solids paste
- No manual intervention
- Key variables: pellet capacity/model bowl size, centrifugation speed and feed rate
- For example, to process 100 L 25% E. coli fermentation, an APD 5.0 (5 L pellet capacity) at 20,000 g, throughput 2 L/min, can produce 25 L packed whole cells. That’s 5 discharges; total processing time is 50 min + discharging time 25 min (5 min/cycle)
- Simplified and Smart Performance
- Designed to reduce overall processing steps and time
- Greatly reduces the amount and cost of downstream filtration
- Complete automation without manual intervention to reduce manual labor costs associated with tube bowl and batch centrifuges
- No exposure of the bioprocess to the ambient air and no exposure of the operators to the bioprocess
- Equipped with PLC control offering built-in recipes for common applications as well as programmable cycle-by-cycle, step-by-step or complete manual operations
- Suitable for processing volume (10-10,000 L) from development to large-scale production using the same centrifuge
- Simple overall construction for easy maintenance
- Simple interior design allows thorough and repeatable CIP and SIP
- Automatic solids discharge , no scrapers, no baffles or discs to impede discharge of retained solids
- Advanced Cell Handling
- Incorporates a gentle processing environment for shear sensitive mammalian cells and bio molecules (e.g. vaccine, DNA and polysaccharides)
- Designed to maintain cells intact and viable during separation and discharge. Maintaining cell intact reduces the impurities and contaminants from cell debris
- Zero air/liquid interface in the system to avoid product oxidation
- No air design excludes any possibility of foaming. Foaming can cause operation disturbance and is also a major shear force to some common bioprocess applications.
- Handles various types of cultures, low-high cell density cultures and even the most challenging viscous biomass (e.g. filamentous fungi).
- Powerful Separation and Automatic Discharge
- APD II centrifuge provides rotational forces up to 20,000 x G. The powerful separation efficiency results in very low liquid entrainment in sediments, which is important in the isolation of solids such as protein precipitates and inclusion bodies. Automatic piston discharge allows users to collect 99.9+% of bio paste with no manual intervention.
- Superb clarifying power maximizes clarification efficiency to remove any impurities and improves recovery and quality of the high-value liquid phase.
- Thermal Control
- Jacketed thermal control allows operations from –10°C to 40°C for temperature sensitive applications with control accuracy of 1°C
- Ensures cGMP Manufacturing
- Build to cGMP and ASME code standards
- Built-in CIP and optional SIP
- Complete hermetic containment to reduce contact risk
- Hazardous (flammable or explosive) area designs available