High differential pressure (ΔP) in a bag filter is typically caused by three core issues:

1. Filter bags are clogged

2. Filter bags are damaged or blinded

3. Incorrect installation or undersized system design

Follow the troubleshooting steps below in order to identify and resolve the problem efficiently.

1. Most Common Cause: Filter Bag Clogging

Symptoms:

• Differential pressure increases gradually over time.

Solutions:

Improve Cleaning Performance

• Increase pulse jet pressure.

• Extend pulse duration.

• Shorten cleaning intervals.

• Perform manual shaking or mechanical cleaning if applicable.

Check the Pulse Cleaning System

• Inspect pulse valves for leakage or malfunction.

• Ensure solenoid valves are operating properly.

• Confirm blow pipes are correctly aligned with filter bag openings.

Temporary Solution

If differential pressure becomes excessively high:

• Shut down the system safely.

• Replace clogged filter bags immediately.

2. Sudden Pressure Spike: Damaged or Blinded Filter Bags

Symptoms:

• Differential pressure rises sharply within a short time.

Solutions:

Inspect Each Filter Bag

• Check for torn bags.

• Look for detached bottoms.

• Inspect loose bag collars or sealing rings.

If any damage is found, replace the affected filter bags immediately.

Oil, Moisture, or Sticky Dust Contamination

If filter bags are blinded due to:

• Oil vapor

• Condensation

• Tar

• Wet or sticky dust

Cleaning will not restore performance. Replacement is required.

Preventive Measures

• Install upstream moisture separators.

• Add oil mist collectors.

• Preheat inlet gas to prevent condensation.

3. Installation or Structural Issues (Often Overlooked)

Poor Bag Sealing

• Air leakage causes unstable or abnormal pressure readings.

• Re-tighten bag collars or replace sealing gaskets.

Tube Sheet Deformation or Air Leakage

• Inspect for warping or cracks.

• Repair by welding or resurfacing.

Incorrect Filter Media Selection

If dust is:

• Fine

• Sticky

• Moist

• Hygroscopic

Upgrade to:

• PTFE membrane filter bags

• Water and oil repellent treated media

• Anti-static filter material (if needed)

4. System or Process Design Problems

Excessive Airflow

If actual airflow exceeds design capacity:

• Differential pressure will remain consistently high.

Solutions:

• Reduce system airflow.

• Increase filtration area.

• Add additional filter bags.

• Upgrade to a larger baghouse unit.

High Inlet Dust Concentration

If dust loading is too high:

• Install a pre-filter system such as:

  • Cyclone separator

  • Baffle chamber

  • Primary filter stage

Quick Troubleshooting Guide

Conclusion

High differential pressure in a bag filter system is usually not a complex problem. In most cases, it results from:

• Poor cleaning performance

• Damaged or blinded filter bags

• Incorrect system design

Systematic inspection—starting from cleaning performance, then filter bag condition, and finally system design—will resolve over 90% of high-pressure issues quickly.