In the production of high-precision products, the air cleanliness of cleanrooms directly determines product quality. With a filtration efficiency of over 99.97% for 0.3μm particles, the pleated high-efficiency filter (HEPA) has become the core equipment of air purification systems.
Its operation relies on the interception and inertial collision effects of filter paper (glass fiber or synthetic fiber), while the partition separates the filter paper to form a uniform air flow channel, enhancing the structural strength at the same time to ensure the stability of filtration.
In the air purification system of clean workshops, HEPA mainly plays two core roles: one is the terminal filtration, which is installed in the supply air system close to the clean room. The air that has been pre-treated by primary and medium-efficiency filters and then deeply purified by HEPA can meet the strict cleanliness level requirements from Class 1 to Class 100, such as preventing tiny particles from adhering to chips in the electronics industry and avoiding performance damage. The second is the fresh air treatment. Outdoor fresh air contains a large amount of dust and microorganisms and needs to be finally filtered by HEPA. After meeting the standards, it is mixed with the return air and sent into the clean room, which not only ensures the health of personnel but also reduces the contamination of products.
In cleanrooms of different industries, the application of HEPA has its own focus: In the electronics industry, in addition to end filtration, HEPA fan filter units (FFUs) are also integrated into key processes such as chip lithography, packaging and testing to achieve local high-precision purification, while filtering electrostatic particles and reducing product scrap rates. The pharmaceutical industry must comply with GMP standards. HEPA not only isolates microorganisms and particles in the supply air system of the production workshop but also prevents the leakage of harmful microorganisms at the exhaust end of the biosafety laboratory. The food industry uses HEPA to filter pollutants in the air supply system, preventing pastries, beverages, etc. from being contaminated during cooling and packaging, and extending their shelf life.
Selection and maintenance are the keys for HEPA to perform effectively: the selection should match the cleanliness level (for example, Class 100 requires a higher filtration efficiency), air supply volume, while also taking into account resistance and service life. Regular maintenance should be carried out by inspecting the appearance (replacing damaged parts in a timely manner), testing the filtration efficiency and resistance (replacing when the threshold is reached), and keeping the area around the filter clean to avoid the accumulation of debris that may affect the performance.
In conclusion, HEPA is the core guarantee for the stable operation of cleanrooms. As the industrial sector’s demand for cleanliness increases, the technological innovation of HEPA will further facilitate high-quality production in various industries.
