Tangential flow is the velocity of liquid flow on the membrane surface
When performing TFF operation, we often encounter some problems: for example, the recovery rate of the target protein is low, and the inlet pressure will increase after filtration for a period of time. Two important parameters and their relationship ensure that the experimental conditions suitable for the sample are determined by exploring and optimizing the experimental conditions. These parameters are summarized into 2 pressure parameters and 2 flow rate parameters.
The pressure difference is the difference between the inlet pressure and the outlet pressure. Transmembrane pressure (TMP) refers to the average pressure difference between upstream and downstream of the filter membrane (TMP = (PF + PR) / 2-pp). The TFF experiments we focus on are differential pressure, transmembrane pressure, tangential velocity and so on. These parameters are closely related. The pressure difference determines the tangential flow and the tangential flow. When the pressure difference is constant, the tangential flow and tangential flow are constant, and the transmembrane pressure controls the speed of liquid filtration. Therefore, the inlet pressure and return pressure must be controlled. These two pressures determine the TMP and the pressure difference. When the pressure difference / tangential flow is constant, TMP becomes the key factor in the tangential flow process, which needs to be optimized.
Tangential flow is the velocity of liquid flow on the membrane surface. It is used to wash away particles to prevent particles from accumulating on the surface of the film. Particles are removed from the membrane surface by the scouring action caused by tangential flow. Inlet pressure and tangential flow (tangential water flow or return flow). When the tangential flow is increased, the pressure difference ∆ p between inlet and return ends will also be increased. If you double the tangential flow rate, you will eventually Δ P double. Partially closing the return valve will increase the TMP and eventually push the liquid through the membrane. The more times the check valve is closed, the greater the TMP, so more liquid will pass through. For most ultrafiltration applications, the osmotic valve is open.
