Patent 9999848 was granted and assigned to Pall Corporation on June, 2018 by the United States Patent and Trademark Office.
A dual bag filter is provided where a replaceable filter element resides in and is sealed to a filter housing. The filter element has a mounting ring, an inner bag, and an outer bag. The inner bag is sized such that it has more surface area than the outer bag and is constrained by the outer bag. The inner bag is formed from a filter medium of different densities such that when the inner bag is crumpled, fluid flow is not restricted.