Membrane filtration device

This invention relates to a membrane based filtration device. More particularly it relates to a porous membrane system which allows for the filtration of products while controlling the transmembrane pressure in the device. One or more hollow fiber membranes having a coflow of filtrate to provide trans-membrane pressure (TMP) control. The membranes preferably are capable or forming a shear effect or Dean vortices at their inner surface. Optionally, the filtrate channel may contain one or more types of beads, either inert or formed of a capture resin such as affinity chromatography beads or ion exchange resins, for selectively capturing and retaining certain molecules from the filtrate of feedstream. The beads, in addition to the optional capture function, aid in the control of the TMP.