Couette membrane filtration with constant shear stress.

Recent developments in the field of blood component separation have revealed the usefulness of membrane filtration using couette type configurations and Taylor vortices as an efficient and effective method. The authors have analyzed in detail the physical and chemical effects on whole blood separated into protein rich plasma, and concentrated red blood cell suspensions, using this technique. The authors also have calculated and demonstrated the technical specifications required to provide laminar flow with Taylor Vortex formation throughout the device, as well as those required to retain constant shear stress on the blood components as viscosity changes. By maintaining constant shear stress below a critical level, it is possible to avoid shear induced hemolysis and to maintain maximal separation efficiency throughout the procedure. The device has further been designed to alter the filtration velocity along the membrane so that the critical filtration velocity is nowhere exceeded, i.e., concentration polarization effects are prevented.