Abstract: A multi-layer bag assembly is used with a housing for collecting particles from air flowing through the multi-layer bag assembly. Multi-layer bag assembly includes at least two bags arranged one inside the other. Each of the bags includes an air permeable filtering material for collecting particles carried by air flowing through the material. The air permeable filtering material being may be the same or different for the at least two bags. The multi-layer bag assembly includes structure for holding the at least two bags in a wide open position. The structure may be a cooperating bag structure incorporated in the at least two bags for cooperating with the housing for selectively holding the respective bags in their respective open conditions. The structure may also be a removable collar attached to at the open portion of the at least two bags, where the removable collar is part of an integral collar of the multi-layer bag assembly.

Abstract: A multi-layer bag assembly is used with a housing for collecting particles from air flowing through the multi-layer bag assembly. Multi-layer bag assembly includes at least two bags arranged one inside the other. Each of the bags includes an air permeable filtering material for collecting particles carried by air flowing through the material. The air permeable filtering material being may be the same or different for the at least two bags. The multi-layer bag assembly includes structure for holding the at least two bags in a wide open position. The structure may be a cooperating bag structure incorporated in the at least two bags for cooperating with the housing for selectively holding the respective bags in their respective open conditions. The structure may also be a removable collar attached to at the open portion of the at least two bags, where the removable collar is part of an integral collar of the multi-layer bag assembly.