11 Apparatus for ventilation, namely, air-conditioning, air-cooling and ventilation apparatus and instruments; ventilation installations, namely, airflow and vertical airflow systems in the nature of air temperature controlled flow systems for air purification, external air treatment units for cleaning and air purification, air dispersion ducts for regulation of air flow and dispensing and distributing air, air purification units in the nature of air showers systems for contamination control; ventilation installations, for clean rooms and operating rooms, namely, airflow and vertical airflow systems in the nature of air temperature controlled flow systems for air purification, external air treatment units for cleaning and air purification, air dispersion ducts for regulation of air flow and dispensing and distributing air, air purification units in the nature of air showers systems for contamination control