Air cleaning units; Air filtering installations; Air humidifying apparatus; Air impellers for ventilation; Air purifying apparatus and machines; Air sterilizers; Dryers for the removal of water vapor from compressed air and gases; Drying apparatus for use in heating, ventilation systems, air conditioning systems and refrigeration systems; Electric air deodorizing apparatus; Electric radiators; Fans for air conditioning apparatus; Filters for drinking water; Gas scrubbing apparatus