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SIngle Pass versus Multi-Pass Filtration

Understanding the two different methods of filtration help to determine the type of filters and systems needed. Single pass filtration is a process of passing fuel through filter medium once. Multi-pass filtration is a process of circulating the fuel through the filter medium an indefinite number of times. For example, if the application is critical requiring a 3µm single pass, then a ß3 = 1,000 rating is recommended. However, if the application is multi-pass then a lesser grade filter may be used to achieve the same result with multiple passes. Costly mistakes can be made by not understanding the application and cleanliness requirement.

The most common single pass filtration is point-of-use. It represents the last chance to clean the fuel and as such should be capable of meeting the rigorous cleanliness requirements. Examples of multi-pass systems include mobile fuel filtration equipment and kidney loop fuel quality management systems. No matter the type of system, understanding the required cleanliness level and the proper filtration to achieve the goal cannot be understated.