BY VEDANT PATHAKBag filter showing high ΔP? A 6-step root cause checklist
Short answer: High differential pressure is the most common dust collector complaint. It's rarely 'just change the bags'.
A rising differential pressure (ΔP) across a bag filter means lower suction at the hoods, dust escaping and a fan working harder. Before you order new bags, run this checklist.
1. Check the cleaning system
- Is compressed air pressure at the header within spec (usually 5–6 bar)?
- Are all solenoid and diaphragm valves firing? Listen to each one
- Is the sequential timer set right for the dust load?
2. Check for moisture
Moisture plus fine dust makes a cake that pulse-jet cleaning can't remove. Look for condensation from gas below dew point, leaking water seals or wet compressed air.
3. Check the air-to-cloth ratio
If the process airflow has grown since commissioning, the filter is undersized. Measure the actual flow and compare it with the design.
4. Check bag media vs. application
Temperature, chemistry and particle size decide the media. Polyester in a hot, acidic stream will blind and fail early.
5. Check hopper discharge
A full hopper re-entrains dust onto the bags. Check the rotary airlock and screw conveyor.
6. Then, and only then, look at the bags
Changing bags without fixing the root cause just resets the clock.
Log the ΔP every shift. A simple trend chart tells you more than any single reading.