Dec 25, 2018 · 1. To determine the pore size of the filter membrane, such as the commonly used 0.22um filter sterilization, 0.45um bacteriological analysis, particle monitoring, biological analysis. 2. The size of the filter membrane, the most commonly used filter membrane diameter is 25mm, 47mm, 13mm, 90mm, 142mm, 293mm, and so on. 3.