Abstract: A vacuum cleaner dust bag that is constructed to substantially increase the filtering action of the bag and therefore is particularly adaptable for use in vacuum cleaners utilized in hospitals, nursing homes, and other health care facilities. The filter dust bag is constituted of two concentric sections or compartments with the space of one of the compartments having a dry filter mat material that effectively traps all dust and dirt particles down to minute particles of about 0.3 microns. The tube on the filter dust bag which connects to the discharge outlet of the vacuum cleaner is constructed of an air-impervious material, while the outer and inner layers of the filter are fabricated of air-pervious material of different elasticity.

Abstract: A filter cloth for a leaf filter of a pressure vessel including a flat retaining sack or bag which encloses the leaf filter. An outlet opening is contained in the sack through which the filtered product can be extracted. A releasable closure device is provided along the greater part of one side edge of the sack to permit removal of the sack from the leaf filter for cleaning and replacement thereof. A reinforcing material is provided at the outlet opening to provide a tight seal about the outlet of the leaf filter. Preferably, the sack is substantially circular but may have any configuration conforming to the shape of the leaf filter.