Proper ventilation of shelters is crucial to ensure safety and comfort. To prevent the entry of nuclear fallout, biological gases, and chemicals in case of war, shelters must undergo effective filtration. Ventilation equipment is necessary to maintain sufficient oxygen levels and minimize exposure to harmful external factors for occupants. In residential areas larger than 800 m², shelters are mandatory in workplaces and military facilities. Ventilation devices are designed as ducted or cellular depending on airflow capacity: devices up to 1,500 m³/h are ducted, while those above 1,500 m³/h are cellular.
Roof fans are usually made of statically painted galvanized sheets. The fan impellers are equipped with backward-curved, sparse blades. The electric motors are powered by 220 and 380 V. Thanks to the internal cooling wheel, body heat is removed from the motor. The fans are manufactured with horizontal and vertical air discharge. In models with vertical and horizontal airflow, the electric motors are standardly placed in a special, protected section.
Roof fans are used as intake fans by connecting air ducts to ventilation slots in buildings or mounted directly on the roof. In roof fans, the fan wheel is mounted directly on the motor shaft. The motion energy generated in the electric motor is transferred to the rotor without losses. Roof fans are produced in two different types: horizontal and vertical. Since these fans have sparse blades and the electric motor is excluded from the air flow, they are also used in hood suction systems. They are used to transport particles of low and medium density.
Roof fans are manufactured in a very compact design. These devices are sought after because they save space. In particular, vertical roof fans enable the transport of odor-contaminated air to higher levels. They operate with high efficiency thanks to a coupled fan system without a pulley system. They can be easily used in hot air transfer projects. Keeping the electric motor out of the airflow prevents it from being influenced by external conditions.