Industrial air filtration is crucial for maintaining safe and clean air quality in industrial settings. Baghouses, which utilize filter bags made of either woven or nonwoven materials, are integral to trapping particulate matter from the airstream. However, without proper maintenance and monitoring, baghouse systems can experience excessively low or high pressure levels. This FAQ article offers tips on troubleshooting and maintaining baghouse systems when differential pressures fall outside normal operating parameters.

Understanding Baghouse Pressure Levels

The baghouse differential pressure drop, or DeltaP, is the pressure difference between the dirty-air side and the clean-air side of the baghouse (across the bags). The amount of airflow and fabric resistance determines this differential pressure. Generally, baghouse pressures should remain steady between 2″ WG and 6″ WG. However, optimal differential pressure can vary based on the application. Factors such as particle size and shape, moisture levels, dust loading, and cleaning effectiveness contribute to the baghouse differential pressure.

When the pressure reading rises above 6″ and approaches 8″ WG after cleaning, it may indicate that your baghouse filter bags are nearing the end of their lifespan and require maintenance.

Maintaining Baghouse Systems with High Pressure

Identifying the source of pressure irregularity is crucial. High differential pressure increases energy consumption, especially with a variable-speed fan, as the blower must work harder, causing additional wear on filter bags, solenoids, and diaphragms.

For unexpectedly high-pressure readings, check the following maintenance items:

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• Cleaning System Functionality: Ensure the cleaning system is working properly. If not, filter bags won't be cleaned during their cycles.

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• Material Discharge Device: Check for proper operation. If it’s leaking or drawing air, dust cannot travel into the upward gas stream.

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• Bag Blinding or Plugging: Dust particles embedded in the filter’s depth can prevent proper airflow, necessitating a filter bag replacement.

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• Excessive Dust Cake: A gradual pressure increase often results from dust accumulating inside the filter media. BronzeWood recommends on-demand cleaning over timed cleaning as the fabric ages or penetrates. Increased cleaning cycles can be recognized with proper monitoring.

Resolving Low Baghouse Pressure

Low-pressure readings in baghouse systems can stem from several causes. A sudden drop below 2″ WG may indicate a filter bag leak, rupture, or plugged ducting. Conduct a leak detection test to identify holes in filter bags, the system’s housing, or other parts.

Other common causes of low-pressure drops include:
 

• Fan Issues: Inspect fan blades for damage and check for slipping belts if the fan isn’t inducing enough airflow.

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• Moisture: Ensure the baghouse environment is dry. Check that seals are effective and ducting has no holes that could draw in moist air.

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• Inlet Deflector Wear: A broken or worn inlet deflector can lead to uneven dust loading, potentially causing some filters to become overloaded with dust, resulting in a pressure drop throughout the system.

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• Venturi Alignment: Proper airflow delivery is crucial for bag inflation. Obstructions can prevent full inflation, causing premature plugging and operational issues.

 

Regular monitoring of your baghouse’s differential pressure and timely action when deviations occur can reduce energy costs, prevent costly repairs, and ensure optimal performance. Investing in maintenance and troubleshooting keeps baghouses in top condition, prolonging filter bag service life.