Ventilation ducts play a very important role and position in the transportation of air supply, exhaust, and carrying waste gas objects, so how do ventilation ducts use ducts to achieve these functions? Ventilation duct ventilation can be achieved using mechanical ventilation or natural ventilation. Ventilation can be divided into three categories: supply air, exhaust air, and supply and exhaust air. According to the different mechanisms of action, ventilation can be divided into two categories: dilution ventilation and displacement ventilation. The following is a brief introduction to the ventilation principle and function of the ventilation duct.
(1) Dilution ventilation
Dilution ventilation is also known as mixed ventilation, that is, sending air with a lower concentration of pollutants than indoor air to mix with indoor air, so as to reduce the concentration of indoor pollutants and achieve hygiene standards.
(2) Displacement ventilation
In the displacement ventilation system, fresh cold air is sent from the bottom of the room at a very low speed (0.03-0.59t/s), and the temperature difference between the supply air is only 2-4Y. The incoming fresh air fills the bottom of the room like water due to its high density, and the thermal convection airflow caused by the heat source makes the indoor vertical temperature Zen, and the airflow rises slowly, leaving the work area, pushing waste heat and pollutants to the top of the room, which is directly discharged from the exhaust port located on the ceiling or at the top of the room.
The indoor air flows like a piston so that pollutants are discharged from the top of the room with the airflow, and the working area is basically in the incoming air, that is, the concentration of pollutants in the working area is approximately equal to the concentration of the incoming air, which is the difference between displacement ventilation and traditional dilution ventilation. difference. Apparently, the ventilation effect of displacement ventilation is much better than that of dilution ventilation.
Ventilation ducts can also achieve local ventilation
Local ventilation is the use of local airflow so that local places are not polluted by harmful substances, resulting in a good air environment.
Local ventilation systems are divided into two categories: local air supply and local exhaust. Local exhaust is to capture and purify pollutants on the spot and discharge them to the outdoors. The local air supply is to send the treated and qualified air to the local work site to ensure the air conditions in the local area.
Local ventilation should be given priority as a technical measure to ensure air quality in working and living environments and prevent indoor environmental pollution.