Pressure Control for Biopharmaceutical Filtration

Filtration is a key step in the manufacturing of biopharmaceutical products. Upstream biopharmaceutical filtration may prepare media or buffer solutions, while downstream filtration typically involves purification focused on isolating the target molecules or compounds. In these steps, the differential pressure across the filter or separation membrane must be carefully maintained in a narrow range.

The Equilibar® dome-loaded back pressure regulator (BPR) offers higher turndown ratio than other valves and can therefore provide precise control across a wide range of flow rates. This makes the Equilibar BPR a superior choice in traditional trans flow or cross flow filtration control.

Our FD series of sanitary BPRs are designed specifically for these applications in which sanitary biopharma equipment must be used. These FD BPRs are made of SS316L and are fitted with USP Class VI diaphragms. They have a crevice-free design and are drainable in certain orientations. The precise and instantaneous control of the Equilibar back pressure control technology make them well suited for biopharmaceutical filtration.

In the biopharmaceutical filtration system schematic above, an Equilibar FD BPR is used in both the retentate and permeate lines at the exit of the trans flow filtration membrane. A setpoint is established on the dome of the BPR using an electro-pneumatic pilot regulator so the Equilibar FD valve can be computer controlled. This allows the filtration system to be controlled by differential pressure (dP) mode – the pressure differential between the feed and retentate streams or by transmembrane pressure (TMP) mode – adjusts the retentate control valve to maintain constant TMP.

note: If cross flow rate (flux) mode is preferred, flow transmitters may be added to the permeate and retentate lines. In flux mode, flow is maintained by regulating the retentate and permeate flow and the Equilibar FD back pressure regulators would act as flow control valves.