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The ventilation system of the environmental protection cabinet (especially the fume hood in the laboratory) is mainly based on the principle of negative pressure and local air supply to ensure the safety of the laboratory operator and effectively eliminate harmful gases and substances generated during the experiment. The following is a detailed analysis of the working principle of the environmental protection cabinet ventilation system:

Principle of negative pressure:

A certain negative pressure environment is formed inside the fume hood through the exhaust system (such as exhaust fans). This negative pressure environment makes harmful gases and particles unable to escape from the inside of the fume hood, but are sucked into the fume hood and then discharged outside through the exhaust duct.

Local air supply:

When the fume hood is working, local air supply is formed in the experiment area through a specific air supply device (such as a low-speed fan), which helps to quickly exhaust harmful gases and particles from the operation area and further ensure the cleanliness of indoor air.