Structure of ePTFE hollow fiber membrane module
The ePTFE hollow fiber membrane module manufacturer tells you that it is essentially a tubular membrane. The main difference between the two is that the hollow fiber membrane has no support and is self-supporting.
The diameter of the membrane used in the ePTFE hollow fiber membrane module is 0.2-2.5 mm, and the ratio of the inner and outer diameters is 2-4, which is higher than that of the capillary membrane (the diameter of the membrane tube is about 3-6 mm) and the tubular membrane (the diameter of the membrane tube is 6-25 mm). Much finer. This kind of membrane is structurally asymmetric, so its compressive strength is supported by its own asymmetric structure, and it can withstand a static pressure of 6MPa without being compacted. The compressive strength of the membrane depends on the ratio of inner and outer diameters, and has nothing to do with the thickness of the fiber tube wall.
The ends of many bundles containing tens to nearly ten thousand fibers are embedded in epoxy or polyurethane adhesive. After cutting the head, the fiber cavity is exposed to form a tube sheet. The shell side is the pressurized side, and the permeate enters the fiber tube and flows out from the open end of the fiber, that is, the external pressure type.
The ePTFE hollow fiber membrane module manufacturer tells you to seal the tube sheet in a plastic or stainless steel cylinder, and form an effective seal with the tube sheet head, O-ring, etc. to ensure that the feed liquid and the permeate are completely isolated, thus forming a hollow fiber type membrane components.
It can be divided into external pressure type and internal pressure type according to the shell side of the feed or the tube side. The way of encapsulation, and whether the feed goes through the shell side or the tube side depends on which separation process the component is used for and the nature of the feed liquid.
The fibers in most ePTFE hollow fiber membrane modules are U-shaped, and one end is sealed and placed in a pressure vessel (membrane shell). The shell side is the pressurized side, and the permeate enters the fiber tube and flows out from the open end of the fiber, that is, the external pressure type.
The manufacturer of ePTFE hollow fiber membrane module tells you that pollution and concentration polarization have a great impact on the separation performance of hollow fiber membranes. By changing the flow mode, membrane pollution and concentration polarization can be improved. For the external pressure type with the cortex outside, according to the feed flow mode, it can be divided into three types: axial flow type, radial flow type, and fiber drum type.