11 AIR CONDITIONERS FOR CONDITIONING AIR OR OTHER GASES BY HEATING, COOLING, HUMIDIFYING, DEHUMIDIFYING, HEAT OR MOISTURE EXCHANGE AND CLEANING, AND CHANNELS AND DUCTS ENCLOSED IN SUCH APPARATUS; HEAT EXCHANGERS-NAMELY, HOT AIR FURNACES, AIR HEATING AND COOLING COILS AND INDUCTION UNITS; FANS, BLOWERS, VENTILATORS, AIR GRILLERS, AIR VALVES, AIR DAMPERS, AIR DIFFUSERS, DRY OR WET FILTERS OR SEPARATORS; AIR DRYERS FOR LUMBER, VENEER, BOARD SHEETS, CELLULOSE, AND OTHER FIBROUS MATERIALS, PAPER CARDBOARD, GRAIN, AND FLASH-DRYERS