An Inside-Out Horizontal Hollow Fiber UF (Ultrafiltration) Membrane is a filtration module in which raw water flows through the inside (lumen) of each hollow fiber, with filtration occurring from the inner surface outward, and the horizontal housing orientation supports easy installation, backwashing, and maintenance in system racks. This configuration is widely used where feed water has higher suspended solids or requires more robust pretreatment before final polishing (such as RO pretreatment).
Construction & Design
Fiber Material: Commonly made from PVC, PVDF, or PES (polyethersulfone) — chosen for chemical resistance, mechanical strength, and long service life.
Fiber Configuration: Thousands of hollow fibers are bundled together inside a horizontal housing, potted at each end with epoxy resin to separate feed and permeate sides.
Flow Path: Feed water enters the fiber lumen (inside) under pressure, and permeate exits through the fiber wall to the outer shell this "inside-out" mode allows for effective handling of higher turbidity feed water compared to outside-in designs.
Pore Size: Typical UF pore size range of 0.01–0.1 micron, effectively removing suspended solids, bacteria, colloids, and some viruses while allowing dissolved salts and small molecules to pass.
Housing: Durable PVC or stainless-steel horizontal shell designed for easy rack-mounting and multi-module skid assembly.
