In chip manufacturing plants, even a speck of dust as small as 0.1 microns can render an entire wafer scrapped; in sterile operating rooms, bacterial intrusion directly threatens surgical safety. In these environments, where cleanliness is crucial, HEPA filters serve as the "last line of defense" protecting the air.
KLC As an industry service provider with years of experience in air purification, we'll break down the technical secrets of HEPA filters and how they create a clean barrier for various industries.
Basic Principles of HEPA Filters
1. Physical Interception: Micron-Scale "Air Screening"
Using ultrafine glass fibers or composite filter media, nanometer-scale pores (over 1,000 times smaller than the diameter of a human hair) are formed between the fibers, acting like a precision sieve that directly intercepts particles larger than these pores. The Shangjing HEPA filter utilizes a gradient pore design, achieving a 99.9% interception rate for particles larger than 5μm.
2. Inertial Collision: Traps Particles
When airflow suddenly changes direction while passing through filter media fibers, larger particles (0.5-10μm) are deflected by inertia and directly collide with and adhere to the fibers. This principle is particularly critical in the high-speed airflow systems of semiconductor plants, quickly capturing fine debris generated by metal processing.
3. Diffusion Effect: A "Brownian Motion Trap" for Nanoparticles
Viruses and nanoaerosols smaller than 0.1μm experience random motion due to molecular thermal motion, increasing the probability of contact with the filter media. Our electrostatically charged filter media technology improves diffusion efficiency by 30%, achieving a 99.99% filtration efficiency for the novel coronavirus (approximately 0.1μm).
4. Electrostatic Adsorption: Giving the Filter Media a "Magnetic Coat"
The electret treatment imparts static electricity to the filter media. The charged fibers can attract particles of opposite charge, even polarizing neutral particles. In PM2.5 control scenarios, this technology can increase the filtration efficiency of submicron particles to over 99.97%.
Its Function and Role in Cleanrooms
Stability Does Not Require Compromise
1. Providing Ultimate Air Purification
High-efficiency filters effectively remove tiny particles, bacteria, viruses, and other harmful substances from the air, ensuring that the air cleanliness within the cleanroom meets predetermined standards. In chip manufacturing workshops in the electronics and semiconductor industry, air cleanliness requirements are extremely high. Even the smallest dust particles can cause chip defects and affect product quality.
High-efficiency filters effectively remove airborne particles 0.3μm or smaller, typically achieving a filtration efficiency of over 99.97% for particles as small as 0.3μm. Some ultra-high-efficiency filters even achieve filtration efficiencies as high as 99.9995%, providing a nearly dust-free clean air environment for chip manufacturing and meeting the stringent air quality requirements of the production process.
2. Maintaining a Stable Clean Environment
High-efficiency filters operate continuously and stably, providing uninterrupted, highly efficient filtration of air entering the cleanroom, thereby reducing the accumulation and spread of particulate matter within the cleanroom. They not only prevent the intrusion of external contaminants but also rapidly remove pollutants generated by human activity and production processes, helping to maintain a stable cleanliness within the cleanroom and achieve a dynamic cleanroom balance.
In medical operating rooms, the movement of personnel and the operation of equipment generate a certain amount of dust and microorganisms. High-efficiency filters continuously filter the air, effectively removing these pollutants and maintaining a high level of cleanliness within the operating room, thereby reducing the risk of surgical infection.
In precision instrument manufacturing workshops, the production process may generate trace amounts of pollutants such as metal debris and dust. High-efficiency filters quickly remove these pollutants, ensuring the air in the workshop remains clean, providing a stable environment for precision instrument manufacturing and safeguarding the accuracy and performance of products.
3. Protecting Downstream Equipment and Products
In cleanrooms, high-efficiency filters are typically installed at the end of the air handling system, providing the final purification step for air entering the cleanroom. This not only ensures the cleanliness of the cleanroom environment but also protects downstream equipment and products from contamination and damage from harmful airborne particulate matter.
In semiconductor manufacturing equipment, key components such as optical lenses and silicon wafers are extremely sensitive to dust. Even the smallest amount of dust particles can cause equipment failure or degrade product quality. High-efficiency filters effectively intercept airborne particulate matter, preventing it from entering the equipment, thus protecting its normal operation and product quality. In aseptic filling plants in the food and beverage industry, high-efficiency filters remove airborne microorganisms and dust, preventing contamination of food and beverage products, extending their shelf life, and safeguarding consumer health.