34 INDUSTRIAL BOILERS, DISTILLATION APPARATUS, CONDENSATION APPARATUS AND PLANTS, AND PARTS THEREOF; AND CENTRAL HEATING SYSTEMS, ROOM HEATERS, HEAT EXCHANGERS, AIR MOISTENERS, AIR MOISTENING PLANTS, DUST COLLECTORS, COMBINED AIR AND GAS COOLERS AND CLEANERS, CENTRAL AIR HUMIDIFYING SYSTEMS, VENTILATORS, CENTRAL VENTILATING SYSTEMS, GAS HEATERS, AIR HEATERS, AND LIQUID HEATERS, AIR HUMIDIFIERS, AIR CONDITIONING PLANTS; COOLERS FOR GASES, VAPOR AND LIQUIDS; HEATED DRYERS FOR SOLID OR GASEOUS MEDIA; ABSORBERS AND ADSORBERS FOR GASES, VAPORS AND LIQUIDS; EVAPORATORS; ALL OF THE FOREGOING GOODS INCLUDING NO ELECTRICAL DEVICES EXCEPT ELECTRICAL MOTORS FOR OPERATING THE SAME