Baghouse Filter Troubleshooting

Situation 1 – Chemical Attack

If your fabric filter bags have deteriorated down the entire length of the bag, then the failure is likely due to an exposure of acid or alkaline outside of what your filter media can withstand. Your gas/ dust pH is among the variables considered to determine the best filter media and fabric construction for your application. There may be blotches, water stains, and discoloration visible on the failed bag.

Situation 2 – Thermal Attack

If your bags are charred or melted when they have worked fine before, it’s likely that build up in the hopper, which traps heat and causes exothermic surge. The filter bag failures in the picture were due to an over-full hopper which engulfed the filter bags caused thermo-degradation.

Situation 3 – Abrasion/Erosion

In pulse-jet filter bags, a broken cage wire can quickly puncture a hole in a filter bag.

If the bottom six inches of the bag are the only point of abrasive failure, it’s likely that other cages are rubbing against it. A filter bag with a wear strip or bump cuff will prolong bag life by doubling the amount of fabric where the abrasion occurs.

If your failed filter bags look like the image shown, then erosion is the issue. Erosion occurs when the linear gas velocities are increased or mis-directed into the filter bags. Common erosion issues include – overfull hoppers, worn or missing baffles, or an uneven distribution of airflow into a compartment.

Situation 4 – Burst Filter Bags

Fabric that has burst just under the cuff or at the disc bottom indicates aggressive filter bag cleaning or poor cage integrity. Baghouse retainer cages should be carefully inspected during each changeout to ensure integrity by replacing worn or broken cages. In the case of fabric bursting, annual used filter bag testing can determine if fabric weakness is caused by excessive pulse cleaning or fabric degradation due to chemical or thermal attack.

Situation 5 – Partial Change-Out, New Bags Blinded Quickly

 Many facilities will change only part of their baghouse filters at one time, in an effort to save on maintenance costs. Partially changing out bags in the collector puts the clean bags on double duty until they are as blinded as the old half. When pulling vacuum, air/gas will follow the path of least resistance into the new, clean filter bag. It will continue passing by the older filter bags in favor of the newer, more permeable bags until the overload balanced out the amount of particles embedded within the filter media of each bag, new or old, and equal airflow is reestablished.

For best performance it is best to do a full change-out of your dust collector.

Situation 6 – Proper Snap Band Installation in Pulse-Jet Baghouses

Snap band filter bags are primarily used in top-load pulse jet baghouses. Fit is always important. To check for a proper fit, grasp the snap band ring and attempt to twist. It should not turn or only turn with great resistance. Feel the inside of the snap ring to make sure the ring has fully expanded with no dimples or kinks in the band surface.

Situation 7 – Find Holes in Baghouse Filter Bags with Leak Detection Tools

Find leaks with our leak detection (glow) powder and black light. This tool can prevent you from changing a whole set of good filter bags to eliminate one hole. Any powder visible outside the cage to the tube sheet indicates a poor bag seal. Powder inside the bag indicates a hole.