Maintenance of primary,medium and HEPA filter

1.All types of air filters and HEPA air filters are not allowed to tear or open the bag or packaging film by hand before installation; the air filter should be stored in strict accordance with the direction marked on the HEPA filter package; in the HEPA air filter during handling, it should be handled gently  to avoid violent vibration and collision.

2.For HEPA filters, the installation direction must be correct: when the corrugated plate combination filter is installed vertically, the corrugated plate must be perpendicular to the ground; the connection between the vertical and the frame of the filter is strictly prohibited from leakage, deformation, damage and leakage. Glue, etc., after installation, the inner wall must be clean, free of dust, oil, rust and debris.

3.Inspection method: Observe or wipe with a white silk cloth.

4. Before the high-efficiency filter is installed, the clean room must be thoroughly cleaned and cleaned. If there is dust inside the air-conditioning system, it should be cleaned and wiped clean again to meet the cleaning requirements. If a high-efficiency filter is installed in the technical interlayer or ceiling, the technical layer or the ceiling should also be thoroughly cleaned and wiped clean.

5. The transportation and storage of HEPA filters should be placed in the direction of the manufacturer’s logo. During transportation, it should be handled gently to prevent violent vibration and collision, and it is not allowed to load and unload.

6. Before installation of the HEPA filter, the package must be unpacked at the installation site for visual inspection, including: filter paper, sealant and frame for damage; side length, diagonal and thickness dimensions are met; frame has burr and Rust spots (metal frame); whether there is a product certificate, technical performance meets the design requirements. Then in accordance with the national standard “clean room construction and acceptance specifications” [JGJ71-90] method of inspection, qualified should be installed immediately.

7. HEPA filter with cleanliness level equal to or higher than Class 100 clean room. Before installation, it should be leaked according to the method specified in “Cleanhouse Construction and Acceptance Specification” [JGJ71-90] and meet the specified requirements.

8. When installing the HEPA filter, the arrow on the outer frame should be consistent with the airflow direction; when it is installed vertically, the direction of the filter paper fold should be perpendicular to the ground.

9. Install a coarse plate or folding filter with the galvanized mesh in the direction of the back of the air. To install the bag filter, the length of the filter bag should be perpendicular to the ground, and the direction of the filter bag should not be installed parallel to the ground.

10. Under normal conditions of use, flat plate, folded type coarse or medium efficiency filter, usually replaced once in January-March, the area where the requirements are not strict, the filter material can be replaced, and then it can be soaked with water containing detergent. Rinse, then dry and replace; after 1-2 times of washing, a new filter must be replaced to ensure filtration efficiency.

11. For bag type coarse or medium filters, under normal conditions of use (average 8 hours per day, continuous operation), the new one should be replaced after 7-9 weeks.

12. For sub-hepa filters, under normal conditions of use (average 8 hours per day, continuous operation), generally used for 5-6 months, should also be replaced.

13. For the above filter, if there is a differential pressure gauge or differential pressure sensor before and after the filter, the coarse filter must be replaced when the pressure difference is greater than 250Pa; for the medium filter, the differential pressure is greater than  330Pa, it must be replaced; for sub-hepa filters, when the pressure difference is greater than 400Pa, it must be replaced and the original filter can not be reused.

14. For HEPA filters, when the resistance value of the filter is greater than 450Pa; or when the airflow velocity of the windward surface is minimized, the airflow speed cannot be increased even after replacing the coarse and medium filter; If there is an unrepairable leak on the surface of the filter, a new HEPA filter must be replaced. If the above conditions are not available, it can be replaced once every 1-2 years depending on the environmental conditions.

15. In order to give full play to the role of the filter, the upstream wind speed of the filter during the selection and use, the coarse and medium  filter should not exceed 2.5m/s, and the sub-hepa filter and high efficiency filter should not exceed 1.5. m / s, this will not only help to ensure the efficiency of the filter, but also extend the life of the filter and save costs.

16. When the equipment is running, generally do not replace the filter; if the filter has not been replaced due to the replacement period, only the coarse and medium  filters can be replaced in the case of non-stop fans; sub-hepa filter and HEPA filter. It must be stopped before it can be replaced.

17. The gasket between the filter and the connecting frame must be tight and free of leakage to ensure the filtration effect.

18. For HEPA filters that need to be used in high humidity and high temperature environments, filter papers with high temperature and high humidity resistance, partition plates and frame materials must be selected to meet the production requirements.

19. The biological clean room and the medical clean room must use the filter of the metal frame, and the surface should be not easy to rust. It is not allowed to use the filter of the wooden frame plate to prevent bacteria and affect the product.xinqi

Post time: May-06-2020