SterliTECH Tip: Maintaining Stable Pressure with Sterlitech Systems
Maintaining stable operating pressure is essential for generating reproducible membrane filtration data. During laboratory-scale crossflow filtration, transmembrane pressure (TMP) may increase over the course of an experiment as operating conditions change. These pressure increases are typically associated with normal system operation, membrane conditioning, or fouling, and can be minimized through proper system adjustment or automated pressure control.
Understanding the factors that influence pressure stability helps improve test consistency and protects both the membrane and filtration system.
Common Causes for Pressure Buildup in Sterlitech Crossflow TFF Systems
- Concentrate Control Valve Adjustment
The concentrate pressure control valve is the primary component used to establish operating pressure. Closing the valve increases back pressure within the system, raising the transmembrane pressure.
If the valve is adjusted too quickly or closed further than necessary, pressure can build beyond the desired operating point upstream through the cell. This is intentional when setting operating pressure, but gradual valve adjustments help maintain stable conditions.
- Membrane Compaction and Fouling
Membrane compaction is a conditioning period during the first 15–30 minutes of operation. As the membrane compresses under pressure, hydraulic resistance increases, which may result in gradual buildup of operating pressure.
Also, fouling can further increase hydraulic resistance, which under constant flow conditions, translates directly to pressure buildup. The pump maintains a programmed flow rate and pressure, so as the membrane fouls, pressure rises.
Maintaining Stable Operating Pressure
- Adjust Concentrate Valve
Maintaining a constant operating pressure requires periodic monitoring of system pressure and adjustment of the concentrate pressure control valve. Monitoring is especially important during the first 15 to 30 minutes of operation and during high pressure operation, when pressure changes are more likely to occur.
- Use Automated Systems
Sterlitech offers an Automated Skid Mount Membrane System designed to automatically control both flow rate and pressure during testing. Pressure is regulated through an automated gas control valve installed on the concentrate line, helping maintain stable operating conditions without the need for continuous manual adjustment.
For existing Benchtop Crossflow TFF Systems, Sterlitech also offers an Automated Gas Regulated Kit that enables automatic concentrate pressure control using the same automated valve technology. With this upgrade, users no longer need to manually adjust the concentrate valve or worry about pressure buildup during operation, resulting in more consistent and reliable testing.
Need Help Optimizing Your Filtration System?
Maintaining stable operating pressure is critical for obtaining reliable membrane performance data. Whether you're selecting the right pressure control solution or troubleshooting changes in system pressure, the Sterlitech technical team can help.
Ask an Expert to learn more about pressure control strategies and automation options for your filtration system.
