Polypropylene(PP) needle felt with Membrane

Micro Filtration membranes are typically pleated with supports and used in cartridges, or die cut into flat parts used in small parts such as vents in medical devices or small filters in injection molded plastic housings. UF, NO and RO flat stock membranes are almost always spiral wrapped and configured into 40” long cylindrical modules. Hollow fiber membranes are usually packed in parallel fashion into cylinders. Fluid flow for MF is almost always perpendicular or “dead-ended” to the position of the membrane with particulate collecting on the surface of the membrane. Whereas, in UF, NF and RO, feed stream flow is parallel to the surface of the membrane as the fluid and particulate “sweep” the membrane surface. In this case, particles constantly transverse the surface and carried away in the majority of the feed stream, while the purified fluid penetrates the membrane. Permeate flow is referred to as “flux”. Feed pressure for MF Cartridges are typically from a few PSI to 20-30 PSI with flow rates measured in gallons per minute. UF, NF and RO have very tight molecular structures and are operated up from 50 to several hundred PSI with flux rates measured in a relatively low number of gallons per square meter of membranes surface area per day. As a result, a systems approach is common with UF, NF and RO separations.