Common Problems and Solutions for Leak Detection of DOP High-Performance Liquid Tank FiltersDOP/PAO High-efficiency Liquid Tank Filter Leak Detection – Common Issues + Directly Applicable Solutions, Engineering-oriented, No Nonsense, Can Be Directly Used for Training / Patrol Inspection / SOP.
I. Upstream Dust Emission Related Issues
1. Upstream Concentration Unable to Rise or Unstable
Possible Causes
Insufficient oil volume in the dust emitter, clogged nozzles, insufficient heating temperature
The dust emission point is too close to the filter, resulting in uneven mixing
Excessive air volume, aerosols are diluted
Solution
Check oil level, clean / replace nozzles, confirm normal heating
Move the dust emission point to a position further upstream in the air duct to ensure uniform mixing
Increase the dust emission volume, wait for the concentration to stabilize for 3-5 minutes before measuring
2. 100% Calibration Failure at the Upstream Photometer
Possible Causes
Probe dirty, pipeline leakage
Concentration too high / too low, exceeding the instrument’s linear range
Instrument not preheated enough
Solution
Clean probe, check air tightness of sampling tube
Control the upstream concentration within 10-20 μg/L
Preheat ≥ 30 minutes, re-zero → 100% calibration
II. Abnormal Leak Detection Reading Issues
3. All filters are too high, but not obvious leakage points
Possible Causes
Incorrect upstream concentration
Photometer not calibrated
Large fluctuations in air volume
Solution
Re-do 100% calibration at the upstream
Confirm stable operation of the system’s air volume for ≥ 30 minutes
Replace clean probe filter
4. Sudden Bursting of the Meter (Obvious Leakage)
Common Locations
Filter material damage
Gumming between filter material and frame
The liquid tank seal not fully immersed, gel missing / aging
Gap between frame and static pressure box
Solution
Small leakage in filter material: Special repair glue / patch (single area ≤ 38mm, total area ≤ 3%)
Liquid tank leakage: Reapply gel, ensure the frame is fully submerged in the gel
Frame leakage: Apply sealant or re-tighten
III. Special Issues of Liquid Tank Sealing (Most Common Pitfalls)
5. Leakage around the entire liquid tank, but filter material is fine
Typical Causes
Insufficient liquid tank gel, dried out, with bubbles
Filter frame not fully pressed down, tilted
Liquid tank deformation, not level
Solution
Replenish / replace liquid tank sealing gel
Reinstall the filter to ensure uniform immersion of all four sides in the gel
Correct the levelness of the liquid tank
6. Only one corner leaks Reason
Insufficient corner gel
Border warping
Uneven installation force
Solution
Focus on replenishing the gel at the corners
Gently adjust and evenly press down
If necessary, replace the filter
Four. Instrument and Operation Issues
7. Reading fluctuates, jumping up and down Reason
The probe is too close and touches the filter material.
The scanning speed is too fast.
There is fluctuation in air volume.
Solutions:
Keep the probe distance at 25-50 mm and do not touch the filter material.
Set the scanning speed to ≤ 5 cm/s.
Wait until the system stabilizes before measuring again.
8. It seems there is no leakage, but the reading is > 0.01%. Reason
Calibration error
Probe contamination
Background aerosol interference
Solution
Re-calibrate the zero position / 100%
Clean or replace the probe
Confirm the background is zero in a dust-free state
V. Handling principles for不合格 after leak detection
Penetration rate > 0.01% = Leakage
Small area leakage of filter material → Repair
Leakage in the liquid tank → Adjustment + Add gel
After repair， re-test the entire area
Exceeding repair standards / Severe damage → Direct replacement
VI. Simplified summary (can be directly written into the SOP)
Inconsistent concentration → Check dusting， check mixing
Local over-limit → Check filter material， check joint， check liquid tank
All around leakage → 90% is leakage of the liquid tank seal
Reading fluctuation → Calibration， probe， scanning speed
Liquid tank filter = Filter material leak detection + Seal leak detection， two key points