Micron Filters are used for fine particle separation purpose and these are typically placed just before the final product isolation to ensure the end product is free from particulate matter.
They are also called as online filters since they are generally mounted on the pipeline which is connecting with final crystallizer where the end product is isolated. Typically a micron filter comes with a catridge type filter to incrase the surface area which helps in higher rate of filtration and housed on a metal body.