Ventilating fans for commercial and industrial use; Industrial air filter machines; Air filtering units; Air filtering installations; Air cleaning units and apparatus in the nature of air cleaning units; Ventilation apparatus, namely, apparatus in the nature of air ventilating units; Apparatus for the exhaust and filtering of smoke, dust, fumes and gases, namely, industrial air filter machines; Apparatus for the exhaust of exhaust gases, namely, ventilating exhaust fans; Apparatus for the exhaust of smells and vapors for large-scale kitchens, namely, ventilating exhaust fans; Air filter systems, namely, air filters for industrial use; Air purification apparatus and units for commercial and industrial use; Ventilation equipment for industrial and commercial use, namely, exhaust fans, exhaust fan systems constituted by exhaust fans, ducts and hoods sold as a unit, exhaust gas extractors with or without nozzles and filtering units