Cartridge Filters for Dust Collectors and Pollution Control Systems

A cartridge filter element is basically a larger diameter pleated filter.  A typical 26″ long element made from cellulose blend fabric has the same filter area as 18 eight-foot long filter bags.  The space advantage of cartridges is apparent and the elements typically provide a higher efficiency than do bags.  The technology for producing cartridge filter media is continually improving, yielding a wider range of available materials than in years past.

Cleaning is by means of a reverse pulse jet.  Due to the high reverse air volume required to clean the large cloth area in a cartridge, a pulse valve is used to clean just a single cartridge, as opposed to a row of bags or 6″ pleated filters.  Cartridge filters operate at low air-to-cloth ratios (more than compensated for by the greatly increased filter area per volume) resulting in lower pressure drops.  Pulsing typically takes place at a lower pressure drop than a bag filter to keep the cake as porous as possible.  Because of the large air volumes handled in cartridge filters, BCE uses a downflow design to eliminate can velocity issues and promote dust settling into the hoppers.

A significant potential problem of bag filters is that during a pulse, dust can be driven at high velocity into adjoining rows of bags which are in the filtering mode, penetrating through the fabric and embedding into the fabric on the clean side during a pulse.  This permanent dust cake increases efficiency, but also pressure drop, and can lead to premature bag blinding.  This is eliminated in a cartridge, since cleaning is normal to the media, essentially tangential to the element rather than radial.

There are certain limitations to the use of cartridge filters.

  • As the pleats are spaced closer than with 6″ pleated filters, cartridges are more limited in maximum inlet dust loading. Too high of a dust loading causes bridging between the pleats, reducing the effective filtering area and increasing the net air to cloth ratio.
  • Cartridges are limited to low temperature applications.
  • As with pleated filters, cartridges should be avoided for dusts that pack or agglomerate.