Product/Service
Choosing The Right Cassette Format
•Datasheet: Choosing The Right Cassette Format
Pall offers a broad range of membrane cassettes for TFF to cover the growing range of potential applications and process volumes.
Five cassette formats are designed for UF and MF applications - Minimate™, Centramate™, Centrasette™, Maximate™ and Maxisette™.
It is important to consider your specific requirements in order to select the most appropriate cassette and format for your application.
Membrane Area Requirements
The process volume and concentration, filtrate flux rate and time requirements must all be considered in order to determine the membrane area required for a specific process. Specify range of expected volumes and calculate area based on largest volume.
- Filtrate Volume - total filtrate volume collected from concentration and diafiltration steps. Filtrate volume can be estimated from the total process volume, concentration factor, and diafiltration volumes required.
- Time Requirements - specify the maximum allowable process time
- Filtrate Flux Rate (FFR) - the rate of liquid passing through the membrane; e.g., L/m2/h (LMH). Tri¬als are required to determine the actual FFR for a product under a specified set of operating param¬eters including transmembrane pressure (TMP), cross flow flux rate (CFF) and temperature.
To estimate membrane area required for a process, use the following equation:
Required Membrane Area = filtrate volume ÷ [average filtrate flux rate x process time]. From the Required Membrane Area calculated, a cassette holder with sufficient capacity can be selected.
Scale-up and Scale-down
Processes are generally developed on a scaled-down system to conserve sample. Ideally, small-scale testing should be performed using a cassette format that has the same path length and channel configuration as the full scale system. Three cassette formats designed for UF and MF applications, Minimate™, Centramate™, and Maximate™, can be used at small scale. Each can be scaled up directly to larger Centrasette™ and Maxisette™ cassettes respectively. This allows direct scale-up by the application of a simple rule: increase membrane area and retentate flow rate in direct proportion to any increase in sample volume. When this formula is applied, the TMP, Cross Flow Flux Rate, and process time will not change appreciably. But if path length is changed, then additional optimization will be required.
•Datasheet: Choosing The Right Cassette Format
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