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The working principle of HEPA (High Efficiency Particulate Air Filter) air purifiers mainly relies on physical filtration technology, which can effectively remove small particulate matter from the air. The following are the core principles and mechanisms of HEPA air purifiers:
The working mechanism of HEPA filter
The design and functionality of HEPA filters are based on four main filtration mechanisms:
Interception mechanism: When larger particles encounter HEPA filters in the airflow, they are directly intercepted due to changes in flow direction and cannot pass through the filter.
Inertial capture: When particles move in the airflow, due to their inertia, they will deviate from the main flow line of the airflow, collide with the filter fibers, and be captured.
Diffusion capture: For very small particles (such as PM0.1), they will randomly move in the airflow due to Brownian motion and eventually be adsorbed onto the filter fibers.
Gravity settling: At lower airflow velocities, heavier particles will settle onto the filter screen due to gravity.
The standard for HEPA filters requires a filtration efficiency of over 99.97% for particles with a diameter of 0.3 microns, making it highly effective in removing pollutants such as smoke, dust, and bacteria.
The combination of HEPA and other filtration technologies
In many air purifiers, HEPA filters are typically used in conjunction with activated carbon filters. Activated carbon is mainly used to adsorb harmful gases and odors in the air, while HEPA filters focus on filtering solid particles. This combination can comprehensively improve air quality, remove particles and toxic gases from smoke.