7 MACHINES FOR HANDLING, PROCESSING AND TRANSPORTING PARTICULATE MATERIALS, NAMELY DUST COLLECTORS, CENTRIFUGAL BLOWERS, AERO-MECHANICAL CONVEYORS, BLOW TANKS, CYCLONE COLLECTORS AND PRODUCT RECEIVERS, AND PARTS THEREFOR, NAMELY ROTARY VALVES AND DIVERTER VALVES; MIXERS AND BLENDERS FOR PARTICULATE MATERIALS; PARTICLE SIZE REDUCTION MACHINES, NAMELY ATTRITION MILLS, KNIFE CUTTERS AND CRUSHERS; SIFTERS AND SCREENERS FOR CLASSIFYING AND SEPARATING PARTICULATE AND PNEUMATIC CONVEYING SYSTEMS COMPRISED OF CONVEYOR DUCTS AND ELBOWS, COUPLINGS, UNLOADING ADAPTORS, AIR FEEDER PICKUP NOZZLES, KNIFE GATES, BUTTERFLY VALVES, MANUAL SWITCH STATION HOPPERS, STORAGE SILOS, INLET AIR FILTERS, INLINE FILTERS, ROTARY AND DIVERTER VALVES, CENTRIFUGAL BLOWERS, BLOW TANKS, CYCLONE COLLECTORS, GRAVITY BLENDERS, ELLIPTICAL ACTION SCREENERS AND RIBBON MIXERS