The daily maintenance of liquid tank high-efficiency filters is a key link to ensure their filtration efficiency, prevent clean environmental pollution and reduce production risks. Maintenance work should be carried out in a targeted manner in combination with its core structure of “liquid tank seal + high-efficiency filter material”. The specific key points are as follows:
I. Basic Inspection: Daily/Weekly regular inspection
Appearance and sealing condition inspection (once a day)
Liquid tank observation: Check whether the sealing liquid in the liquid tank is clear, free of turbidity, odor, and floating impurities (such as dust and flocs). Check whether the liquid level is within the specified range (usually 1/2-2/3 of the liquid tank height, please refer to the equipment manual for details). If the liquid level is too low, replenish the same type of sealing liquid in time (avoid mixing different brands or types to prevent chemical reactions from damaging the sealing effect).
Filter material appearance: Check through a transparent observation window (or regular disassembly and inspection) whether there is any damage, deformation or bulging on the surface of the filter material, and whether the edge fits tightly with the sealing part of the liquid tank without lifting edges or gaps. (If damage to the filter material is found, the machine should be stopped immediately for replacement to prevent unfiltered air from directly entering the clean area.)
Surrounding cleaning: Clean the dust and debris from the filter housing and the surrounding area to prevent accumulated substances from being carried into the liquid tank or filter material by the airflow, which may affect the filtration effect.
2. Differential pressure monitoring (Daily recording, weekly analysis)
Calibration of differential pressure gauge: Confirm that the differential pressure gauge is in a normal working condition (without pointer jamming or zero offset). Calibrate it once a month to ensure the accuracy of the data.
Numerical judgment: Record the pressure difference value of the “air inlet side – air outlet side” of the filter and compare it with the initial operating pressure difference (the reference value when a new filter is put into use)
If the pressure difference increases by 20% to 30% compared to the initial value (for example, if the initial pressure difference is 150Pa and it rises to 180-195Pa), it indicates that the filter material is severely clogged and needs to be replaced.
If the pressure difference suddenly drops (for example, from 160Pa to below 80Pa), it may be due to the damage of the filter material or the failure of the liquid tank seal. The leakage point should be investigated immediately.
Ii. Specialized Maintenance of the liquid tank: Monthly in-depth maintenance
1. Replacement of sealing fluid and cleaning of the liquid tank (once every 1-2 months, or adjusted according to the deterioration of the sealing fluid)
Drain the old liquid: Close the air inlet valve of the filter, open the drain valve of the liquid tank, and thoroughly drain the old sealing liquid (to prevent the residual liquid from mixing with the new liquid and causing performance degradation).
Liquid tank cleaning: Rinse the inner walls of the liquid tank with purified water (or solvents that meet industry cleaning standards), with a focus on cleaning impurities and dirt in corners and sealed tanks. If necessary, gently scrub with a soft-bristled brush (do not use hard tools to prevent scratching the inner walls of the liquid tank and affecting sealing).
Add new liquid: After the liquid tank is dry, slowly add new sealing liquid to the specified level. During the process, avoid generating air bubbles (air bubbles may cause air leakage. Let it stand for 10-15 minutes until the air bubbles dissipate before starting the filter).
2. Sealing structure inspection (once a month)
Check whether the connecting bolts between the liquid tank and the filter housing are loose. If they are loose, tighten them evenly (avoid excessive force causing deformation of the liquid tank).
Check whether the sealing rubber strips (if any) are aged or cracked. If any damage is found, replace them with rubber strips of the same specification in time to ensure the integrity of the seal.
After starting the filter, use the “smoke test method” (or a dedicated leakage detection instrument) to check if there is any air leakage around the liquid tank. If a leakage point is found, the machine must be stopped immediately for handling.
Iii. Filter Material Maintenance: Replace as needed and operate in accordance with standards
1. Criteria for filter material replacement
The pressure difference reaches the “replacement threshold” (usually 1.5 times the initial pressure difference, or as specified in the equipment manual);
Obvious damage, holes and deformation of the filter material layer appeared on the surface of the filter material.
If the air cleanliness test in the clean area fails to meet the standard and other pollution sources (such as air conditioning systems and supply air outlets) are excluded, it is determined that the filter material has failed.
2. Operating Specifications for Filter Material Replacement
Environmental preparation: Before replacement, the area around the filter should be cleaned and disinfected to prevent the introduction of contaminants during the replacement process. Operators must wear clean suits, gloves and masks, and meet the operation requirements of the clean area.
Removal of old filter material: Turn off the power supply of the filter and the air inlet and outlet valves. Loosen the filter material fixing devices (such as pressure strips, bolts), and slowly remove the old filter material (to prevent dust on the filter material from falling off and contaminating the clean area, the old filter material should be sealed and disposed of in accordance with the hazardous waste treatment standards).
Installation of new filter media: Check that the model and specification of the new filter media match those of the original filter. After removing the packaging, gently place it into the filter media tank to ensure full contact between the filter media and the sealing liquid in the tank, with no lifting or gaps at the edges. When installing the fixing device, apply uniform force to avoid damaging the filter material.
Post-installation inspection: Start the filter, monitor whether the pressure difference returns to the normal range, and conduct leakage detection at the same time. After confirming there is no leakage, run continuously for 24 hours, and retest the cleanliness of the clean area. Only when it meets the standards can normal production be resumed.
Iv. Maintenance Records and Emergency Response
1. Establish and maintain archives
Record in detail the time, content (such as inspection items, replaced parts, type of sealing fluid added), and detection data (such as pressure difference values, leakage detection results) of each maintenance to form a complete maintenance ledger, which is convenient for tracing the operation history of the filter and predicting the next maintenance cycle.
2. Emergency response measures
Sudden leakage: If leakage from the liquid tank is detected during operation, the machine should be stopped immediately, the sealing liquid drained, and the leakage point inspected (such as damage to the liquid tank or failure of the sealing rubber strip). Minor damage can be temporarily repaired with special sealing glue, while severe damage requires replacement of the liquid tank.
Sudden failure of filter material: If the clean area is contaminated due to damage to the filter material, production must be immediately halted, the filter material replaced, and a thorough cleaning and disinfection of the clean area carried out. Production can resume only after the cleanliness test meets the standards.
The pressure difference often fluctuates: If the pressure difference suddenly rises or drops sharply, the machine should be stopped first to investigate the cause (such as filter material blockage, valve failure, seal failure), to avoid forced operation which may cause damage to the filter or deterioration of the clean environment.
V. Long-term Maintenance Precautions
Avoid frequent start-up and shutdown of the filter: Frequent start-up and shutdown may cause the sealing liquid in the liquid tank to shake and overflow, or the filter material to deform due to air flow impact. It is recommended to operate stably according to the production plan.
Storage of sealing liquid: Sealing liquid should be stored in a cool, dry and dark environment, avoiding deterioration caused by high temperature and direct sunlight. The storage period should not exceed the product’s shelf life.
Regular professional testing: Every year, a third-party testing institution is invited to conduct a comprehensive test on the filtration efficiency and leakage rate of the filter to ensure compliance with industry cleanliness standards (such as ISO 14644-3).
Through the above daily maintenance measures, the filtration performance of the liquid tank high-efficiency filter can be effectively guaranteed, and its service life can be prolonged (usually 1-2 years, depending on the usage environment), providing a stable production environment for industries with high cleanliness requirements such as electronic component manufacturing.
