|What is Normalized Water Permeability?||NWP is a measure of the ability of pure water to pass through the filter membrane. NWP is a property of the TFF system and is contributed to by the membrane as well as the feed and permeate flow paths in the filter.|
|How is NWP measured?||NWP is measured by filtering pure water throught he system at controlled cross flow, Trans Membrane Pressure and temperature. The filtrate flow rate is measured. The flow rate is normalized to the membrane area, TMP and temperature.
Please refer to the operator's manual or contact Techical Service for further questions regarding the calculation of NWP.
|How does NWP aid in effective cleaning procedure development?||Fouling and polarization leave residues on the membrane that can reduce filter permeability. Effective cleaning removes these residues, restoring the permeability of the membrane. Ideally, NWP after cleaning should equal NWP before use although there can be variation up to +/-15% due to membrane compaction under pressure and measurement error.
NWP validates the ability of cleaning to restore filtration rate of a system.
|Can the Prep/Scale cartridge or holder be autoclaved?||Neither the Prep/Scale cartridges or holder may be autoclaved. The maximum temperature for both of these pieces is 50 degrees Celsius, 122 degrees Farenheit.|
|How do you integrity test the Prep/Scale cartridge?||One would integrity test a Prep/Scale cartridge by performing a diffusion test. A diffusion test is very unlike that of a bubble point test. For specific parameters and procedures see the Maintenance Procedure Manual literature number P34409.|
|How many gauges come with the Prep/Scale holder?||Only one analog pressure gauge comes with the Prep/Scale holder. If you desire operation with two gauges, you may purchase an extra analog pressure gauge with catalog number: B26524. Alternatively, you may purchase the Digital Pressure Gauge Kit which contains two high accuracy pressure gauges with 3/4" sanitary clamp fittings to attach to the Prep/Scale holder.|
|Is it necessary to operate the Prep/Scale cartridge with the Prep/Scale holder?||No, it is not necessary to operate the Prep/Scale cartridge with the Prep/Scale holder. It is possible to operate a cartridge with the bare minimum of a ring stand to hold the cartridge, a retentate clamp, tubing, and a pump. It is recommended to include gauges into the system (one on the retentate and one on the feed), but not entirely necessary. The Prep/Scale holder offers a much higher level of convenience and accuracy. The built-in retentate clamp allows for more precise and sensitive adjustment of the retentate line, the gauges have easily accessible and convenient fittings, the holder can lower the minimum working volume by eliminating part of the tubing requirement for set- up without a holder, and it makes it possible to have an easy sanitary set-up|
|Is the Prep/Scale product line linearly scalable?||No, the Prep/Scale product line is not linearly scalable. For TFF applications, the Pellicon products are the only line linearly scalable systems.|
|What are the minimum working volumes for each of the Prep/Scale cartridges?||The 1 ft2 cartridge has a minimum working volume of 100 mL, the 2.5 ft2 has 150 mL, and the 6 ft2 cartridge has a minimum working volume of 250 mL. These volumes include the tubing volume, and depend on the set-up of the entire system.|
|What volume can I process with each of the units in the Prep/Scale product line?||The Prep/Scale-TFF-1, 0.1m2 (1ft2) cartridge is typically used for processing volumes of ~500 mL up to ~10 L.
The Prep/Scale-TFF-2, 0.23m2 (2.5ft2) cartridge is typically used for processing volumes of ~10 L up to ~50 L.
The Prep/Scale-TFF-6, 0.54m2 (6 ft2) cartridge is typically used for processing volumes of ~50L up to ~100L.
It is important to note, however, that really there is no upper or lower volume limit per cartridge. What needs to be kept in mind is that the larger the cartridge the larger the surface area, the faster the processing, and the larger the hold-up volume. Conversely, the smaller the cartridge, the lesser the surface area, the slower the processing, and the lesser the hold-up volume. The Prep/Scale-TFF-2 cartridge can process a volume about 2.5X faster than the Prep/Scale-TFF-1 cartridge, and the Prep/Scale-TFF-6 cartridge can process a volume about 2.5X faster than the Prep/Scale-TFF-2 cartridge.