Air distributors providing room ventilation, air flow at a certain distribution angle and air outflow, as well as protection against foreign objects - all these are ventilation grilles of ventilation systems. Usually they are installed in places of entry or exit of air. The distribution of air flow directly depends on the shape and design of this type of air distributor.
The grilles can perform both supply and exhaust functions as a whole (in interior ventilation), and separately, only supply and exhaust. Connected to a system that includes ducts made of galvanized steel or other metal, they facilitate the outflow of air. Such options are usually installed in the bathroom and in the kitchen. The shape of the lattice in this case can be absolutely any, the holes are most often of the "honeycomb" type - that is, evenly distributed over the entire area without a slope, resembling a honeycomb. Thus, the exhaust air directly enters ventilation ducts and is relegated outside the house.
But venting ventilation grilles alone are not able to solve the issue of air purification in the kitchen. Here it is necessary to organize a more powerful forced ventilation - since this place is the most powerful source of all kinds of smells in a house or apartment. To enhance air movement, grilles with adjustable air flow can be used - a special fan is installed on them. The most common solution is the equipment of cooker hoods.
Hoods there are two options. The first is with a recirculation system, when the device drives the air flow through its own filters and thus cleans it. Another option is exhaust hoods. To connect them to the ventilation system, special galvanized steel ducts with flexible structure. As a rule, they are hidden in decorative boxes or built-in wall cabinets. It is important that the diameter of the hood coincides with the diameter of the duct - only then the exhaust air, saturated with carbon dioxide and odors, will be properly discharged into the ventilation ducts of the building. To prevent backflow of air, an anti-return valve is usually installed at the junction. Please note: when buying hoods, air ducts and valves are usually purchased separately.