Absolute vs. Nominal Rating   Air Flow   Bubble Point   Depth vs. Membrane Filtration   DOP Test   Filter Efficiency   Filter Life   Frazier Test   Gurley Test   Hydrophilic vs. Hydrophobic   Water Breakthrough   Water Flow/Flux   Our commitment to customer service and technical support is firmly rooted in the philosophy that it is our obligation to help you, the customer select the right microporous membranes for membrane applications.   Membrane Technology Overview Microseparation Process of dividing a homogenerous liquid or gas stream into separate components. Ingredients can be recovered for study or for further separation or filtration.   Microfiltration Process of removing minute solid or gelatinous particles from a liquid or gaseous stream through the use of a porous membrane medium. Generally involves membrane in pore size of 0.03-5 μm range.   Membrane pore size ratings refers to the size of a specific particle or organism retained by the filter to a specific degree of efficiency. Pore size also affects flow rate, back pressure, and the life of the filter. The pore size of filter media is identified by the diameter of the particle that it can be expected to retain with a defined, high degree of efficiency. Pore sizes are usually stated in micrometer (μm), which equals one millionth of a meter. Pore size ratings refer to the size of a specific particle or organism retained by the filter media to a specific degree of efficiency. Ratings can be stated as either absolute or nominal pore size. Measurement of the smallest particle that a filter repeatedly retains. An absolute pore size rating specifies the pore size at which a challenge organism of a particular size will be retained with 100% efficiency under strictly defined test conditions. Among the conditions that must be specified are: test organism (or particle size), challenge pressure, concentration and detection method used to identify the contaminant. Measurement of the smallest particle a filter retains typically at a 90-98% efficiency level depending on manufacturer's claim. A nominal pore size rating describes the ability of the filter media to retain the majority of particulate at (90-98%) and greater than the rated size. Process conditions, such as operating pressure and concentration of contaminant, have a significant effect on the retention efficiency efficiency of the filters. 　　　　　　　　　　　　　 Application 　 Pore Size (μm) Mycoplasma removal　 0.1 Liquid sterilization 0.1-0.2 <3 μm column packings 0.2 Clarification 0.45-1.0 >3 μm column packings 0.45 Venting 0.2-0.45 Prefiltration 0.8-5.0 (1) Define your application requirements (2) Select a compatible membrane (3) Choose the most effective and efficient pore size

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