Patent ID: 8151733

Claim:
A filter top assembly for use with a cage bottom, the cage bottom having a bottom wall and a plurality of side walls defining an opening and a lip disposed on the opening, the filter top assembly capable of covering the opening, thereby enclosing the cage bottom, the filter top assembly comprising: a bonnet having a top wall having a plurality of air passages; one or more projections formed on the top wall to support a filter, wherein each projection is constructed and arranged to suspend the filter and define a substantially uniform filter space between the filter and the plurality of air passages across the bonnet; one or more flanges extending downward from the top wall, the one or more flanges constructed and arranged to engage the lip of the cage bottom to secure the filter top to the cage bottom; and one or more peripheral flanges extending laterally, the one or more peripheral flanges constructed and arranged to restrict any lateral movement between the bonnet and the cage bottom.