Quattroflow® four-piston diaphragm pumps in TFF applications

The production of biologics for the development of biopharmaceutical drugs and therapeutics requires precise, reliable, and safe processes. One of the most common and critical of these steps is tangential flow filtration (TFF), also known to some as “cross-flow filtration.” TFF is a filtration process in which the biological feed stream is passed tangentially across the filter membrane, with an overpressure on the permeate side. As the biological feed stream flows across the membrane, the liquid stream containing molecules or particles smaller than the pore size of the membrane passes through the membrane. Meanwhile, the retentate remains on the feed side of the membrane. The key advantage of TFF is that the substances remaining on the filter, which can clog the filter, are washed away (retained in the flow) during the filtration process. This enables higher efficiency and uptime of the filter. In comparison, dead-end filtration—in which the stream is pressed directly through the membrane—is much more susceptible to blockages as solids are deposited on the filter surface. TFF has therefore established itself as a particularly effective and economical method for concentrating and purifying product streams.

The four-piston diaphragm pumps from PSG Biotech's Quattroflow® product brand offer an effective pumping solution for TFF applications that meets the operating requirements of centrifugal, peristaltic, rotary lobe, and piston pumps. They excel in TFF applications because their four-piston design requires no mechanical seals or rotating parts that come into contact with the media. The product is completely contained, which minimizes shear forces, pulsations, particles, and heat transfer, ensuring gentle handling of biological materials. The pump's mode of operation also offers risk-free dry running, self-priming, and a high turndown ratio, which enables the creation of a wide flow range, especially with regard to changing viscosities. The optionally integrable Q-Control control system further expands the functionality. It enables automatic communication with pressure and flow sensors. This allows the pump to adapt independently to changing process conditions or to shut down automatically in the event of a critical incident, minimizing manual intervention and increasing process reliability.