Abstract: In a vacuum cleaner, a two stage filter system includes a primary inner filter such as a conventional vacuum cleaner filter, and a secondary outer filter with an enhanced surface area that is a self-cleaning, flexible interlocking knitted fabric having a rest position at atmospheric pressure, and a stretched position when under vacuum of a vacuum cleaner, the fabric having at least enough stretchability to increase its surface area, including fabric and interstices, by at least 2% in its stretched position from its rest position. When the vacuum cleaner is operating, the secondary filter is in its stretched position and collects dust and debris, and when the vacuum cleaner is off, the secondary filter relaxes, returns to its rest position and its surface area contracts to be self-cleaning, and a portion of the dust and debris to fall from the filter.

Abstract: A filter kit with an enhanced surface area filter and cage, for an electric power vacuum cleaner, the filter is a self-cleaning, flexible interlocking fabric having a rest position at atmospheric pressure, and a stretched position when under vacuum of a vacuum cleaner, the fabric having at least enough stretchability to increase its surface area by at least 10% in its stretched position from its rest position. When the vacuum cleaner is operating, the filter is in its stretched position and collects dust and debris, and when the vacuum cleaner is off, the filter relaxes, returns to its rest position and its surface area contracts to be self-cleaning, and a portion of the dust and debris to fall from the filter.

Abstract: A filter kit with an enhanced surface area filter and cage, for an electric power vacuum cleaner, the filter is a self-cleaning, flexible interlocking fabric having a rest position at atmospheric pressure, and a stretched position when under vacuum of a vacuum cleaner, the fabric having at least enough stretchability to increase its surface area by at least 10% in its stretched position from its rest position. When the vacuum cleaner is operating, the filter is in its stretched position and collects dust and debris, and when the vacuum cleaner is off, the filter relaxes, returns to its rest position and its surface area contracts to be self-cleaning, and a portion of the dust and debris to fall from the filter.