What details should be noted when installing and maintaining HEPA filters in the air shower room?

When installing and maintaining high-efficiency filters in the material shower room, it is necessary to start from the details to ensure their filtration efficiency and the stability of equipment operation. The following are specific precautions and key points of operation:
I. Key Points for Installing High-Efficiency Filters
1. Preparations before installation
Environmental cleaning: Before installation, the interior of the material shower must be thoroughly cleaned to remove dust and debris, preventing contaminants from entering the system during installation.
Filter inspection
Visually inspect the appearance of the filter to ensure there is no damage or deformation, no wrinkles or breaks in the filter paper, and no looseness in the frame.
Check whether the model and size of the filter match the design of the air shower, and confirm that the filtration efficiency grade (such as HEPA, ULPA) meets the cleanliness requirements.
Tools and Protection: Prepare dust-free gloves, sealant, wrenches, and other tools. Operators must wear clean suits to prevent human particles from contaminating the filter.
2. Key operations during the installation process
Installation direction
High-efficiency filters are usually marked with the airflow direction (such as "→"), and it is necessary to ensure that it is consistent with the supply air direction of the material shower room to avoid installing it in reverse and causing a decrease in efficiency.
For filters with separators, the separators should be perpendicular to the ground to prevent the filter paper from sagging due to gravity and affecting the filtration effect.
Sealing treatment
Sealant (such as silicone sealant) or a gasket should be used between the filter and the installation frame to ensure there are no air leakage gaps. The sealant should be evenly applied with a thickness of approximately 3 to 5mm. After installation, squeeze it until there are no air bubbles.
If there is any unevenness at the edge of the frame, it can be filled and leveled with sealant to prevent short circuits in the airflow.
Fixed method:
When fixing the filter with bolts or clamps, apply force symmetrically and evenly to prevent the frame from deforming and damaging the filter paper.
For large air volume air shower rooms, fixed points can be added to prevent the filter from shaking under the impact of air flow.
3. Inspection after installation
Leak detection test: Use an aerosol generator and a particle counter for scanning leak detection, with a focus on checking the edge of the filter, the sealant area, and the connection points of the frame. Any leakage points need to be filled with sealant or reinstalled.
Resistance test: Record the initial resistance value after installation as a reference for later maintenance (the normal initial resistance is generally 200-400Pa, depending on the model).
Ii. Maintenance Details of High-Efficiency Filters
1. Daily operation and maintenance
Pre-filter replacement: The front end of the material shower room is usually equipped with primary or medium-efficiency pre-filters, which need to be replaced regularly (primary filters every 3 to 6 months, medium-efficiency filters every 6 to 12 months) to prevent the failure of pre-filters from causing excessive load on high-efficiency filters.
Surface cleaning: Regularly wipe the protective screen at the front end of the filter with a lint-free cloth to remove visible dust and prevent dust accumulation from blocking and affecting the air volume.
Operation status monitoring
The resistance of the filter is monitored in real time through a differential pressure gauge. When the resistance reaches twice the initial value (for example, from 250Pa initially to 500Pa), it needs to be replaced promptly.
Observe whether the air volume of the goods shower room has significantly decreased. If the air volume drops by more than 20%, it might be that the filter is clogged and the resistance needs to be checked.
2. Regular in-depth maintenance
Internal cleaning: At least once a year, conduct a dust-free cleaning of the box body and supply air ducts of the air shower to prevent dust accumulation from causing secondary pollution to the filters.
Seal inspection: Check whether the sealant is aged or cracked, and whether the gasket is deformed. Replace the failed parts in time to prevent air leakage.
Air flow uniformity test: Use an anemometer to measure the air velocity at the outlet to ensure that the deviation of air velocity at each point does not exceed 15%. If it is uneven, it may be due to local blockage of the filter or installation issues.
3. Handling of special circumstances
Accidental contamination: If liquid splashing or dust leakage occurs inside the material shower, the machine should be stopped immediately. Check whether the surface of the filter is contaminated and replace it in advance if necessary.
Shutdown protection: Before a long-term shutdown (more than one month), the material shower room needs to be cleaned, and the air inlet valve should be closed to prevent external contaminants from depositing on the surface of the filter.
Iii. Safety and Operating Procedures
Power-off operation: When maintaining or replacing the filter, the power supply to the material shower room must be cut off to prevent personnel injury or filter damage caused by the operation of the fan.
Disposal: The replaced high-efficiency filter may adsorb harmful particles. It should be sealed in a plastic bag and treated as hazardous waste to avoid direct disposal.
Personnel training: Operators need to receive professional training, be familiar with the installation process and maintenance points, and avoid affecting the filtration effect due to improper operation.
Summary
The installation and maintenance of high-efficiency filters need to take into account sealing, directionality, cleanliness, and monitoring mechanisms. By controlling the details, the service life can be extended to ensure the cleanliness of the air shower. Regularly recording resistance data, pre-filter replacement cycles, and maintenance conditions can help formulate more scientific maintenance plans and reduce operating costs.