● Mechanical Ventilation: Exhausting indoor air through ventilation equipment such as ventilators (fans) while introducing fresh air from outdoors. The pressure difference generated by the ventilator causes air to flow through the system, discharging polluted indoor air and introducing relatively clean outdoor air to maintain the freshness and quality of indoor air.
● Natural ventilation: Utilizing the temperature difference between indoor and outdoor, wind pressure and other natural factors to promote air exchange through doors, windows, vents and so on.
2. Principle of air purification
● Physical filtration: When air passes through a filter, the particles in it will be blocked and captured by the fibers, filters and other physical structures in the filter. Common filters include primary filters, intermediate filters and high efficiency filters (HEPA filters), which can remove particles of different particle sizes, such as dust, pollen, bacteria, viruses and so on.
● Adsorption purification: Using the porous structure and surface properties of adsorbents (such as activated carbon), it adsorbs harmful gas molecules in the air, such as formaldehyde, benzene, sulfur dioxide, nitrogen oxides, etc., and fixes them on the surface of the adsorbent, thus purifying the air.
● Chemical purification: through chemical reactions to convert air pollutants into harmless or low-harm substances. For example, chemicals are used in air purification devices to oxidize, reduce, neutralize and other reactions with harmful gases to remove them.
● Ultraviolet sterilization: ultraviolet light has the effect of sterilization, through the ultraviolet light irradiation air, so that the air microorganisms (such as bacteria, viruses, fungal spores) of the DNA or RNA structure has been damaged, so as to lose the ability to reproduce and survive, to achieve the effect of sterilization and purification.
3. Principle of airflow organization
● Directional airflow: through the reasonable arrangement of air supply and exhaust ports, the air flows in a predetermined direction, forming a directional airflow pattern. Common airflow patterns include laminar flow (unidirectional flow) and turbulent flow (non-unidirectional flow). Laminar flow mode, the air flows at a uniform speed along parallel streamlines, suitable for laboratories with extremely high cleanliness requirements; turbulent flow mode, the air flows in irregular directions and speeds, suitable for laboratories with general cleanliness requirements.
● Negative pressure control: For some laboratories that may produce harmful gases, dust or biological pollutants, the ventilation system enables the formation of negative pressure indoors, i.e., the indoor air pressure is lower than the outdoor air pressure. This prevents pollutants from leaking outside and protects the outdoor environment and personnel safety.