Liquid leakage in a bag filter housing is a common issue in industrial filtration systems. Effective repair follows three core steps: stop and depressurize the system, locate the leak source, apply targeted repair, and finally perform pressure testing.
Most leaks originate from three areas:
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Sealing components
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Housing / flange / piping connections
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Filter bag or support basket damage
Below is a practical, step-by-step repair guide suitable for on-site maintenance.
1. Most Common Leak Source: Sealing Areas
Leaks often occur at the filter bag sealing zone or the lid flange gasket.
1.1 Leakage at Filter Bag Collar Seal
Repair Steps
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Open the housing and remove the filter bag.
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Clean sealing surfaces on both the bag collar and sealing seat using lint-free cloth and suitable solvent or water. No particles should remain.
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Inspect the bag collar:
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Replace if torn or deformed.
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Slight deformation may be corrected, but food or pharmaceutical applications require replacement.
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Reinstall the bag carefully, ensuring:
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Proper seating in the sealing groove
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No wrinkles or misalignment.
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1.2 Lid Flange Gasket Leakage
Repair Steps
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Remove and inspect gasket for aging, cracks, or deformation.
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Replace if damaged, selecting material according to service conditions:
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NBR: general applications
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FKM/Viton: chemical resistance
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Silicone: food-grade applications
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Clean flange surfaces; polish light scratches with fine sandpaper.
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Reinstall gasket and tighten bolts evenly in a diagonal pattern to ensure uniform compression.
2. Housing, Flange, or Pipe Connection Leakage
2.1 Housing or Weld Seam Seepage
Temporary Repair
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Clean and roughen leak area.
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Apply chemical-resistant repair compound or leak sealant.
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Allow proper curing before testing.
Permanent Repair
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Professional welding repair or housing replacement.
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Pressure vessels must be repaired only by qualified personnel.
2.2 Flange or Pipe Joint Leakage
Repair Steps
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Check bolt tightness and tighten evenly.
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Replace flange gasket if leakage persists.
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For threaded connections, replace seals or fittings if tightening fails.
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Welded joints require professional re-welding.
3. Leakage Caused by Filter Bag or Basket Damage
3.1 Filter Bag Damage
Signs include holes or fine tears allowing contaminants to pass.
Repair
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Replace with a correctly rated filter bag.
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Confirm material compatibility with temperature, chemicals, and filtration precision.
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Check basket interior for sharp debris before installation.
3.2 Support Basket Deformation
A distorted basket may puncture bags.
Repair
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Slight deformation can be corrected manually.
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Replace basket if cracked or severely deformed.
4. Mandatory Step After Repair: Pressure Testing
Always test before restarting operation.
Testing Procedure
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Close outlet valve.
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Slowly fill housing and vent trapped air.
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Gradually increase pressure to rated working pressure.
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Hold pressure for 10–15 minutes.
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Inspect all sealing points and connections.
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Restart system only after confirming zero leakage.
5. Preventive Maintenance to Avoid Leakage
Proper routine maintenance significantly reduces leak incidents.
Recommended practices:
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Install filter bags carefully and keep sealing surfaces clean.
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Tighten lid bolts evenly without excessive torque.
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Replace aging gaskets and bags regularly.
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Avoid operating beyond rated pressure or temperature limits.
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Clean and inspect baskets periodically.
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Maintain a maintenance log for inspections and replacements.
6. Special Note for Food, Pharmaceutical, and High-Purity Applications
In hygienic systems:
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Temporary leak sealants must not be used.
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Damaged components must be replaced immediately.
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Equipment must be cleaned and sterilized after repair to maintain sanitary compliance.
Conclusion
Most bag filter leakage issues are linked to sealing failures, damaged filter elements, or structural connection issues. Prompt troubleshooting combined with preventive maintenance ensures stable operation, reduces downtime, and extends equipment service life.