MACHINES AND PARTS THEREFOR FOR USE IN THE PLASTICS PRODUCTION AND PROCESSING INDUSTRY-NAMELY, BLENDERS, LOADERS, COLORING LOADERS, PNEUMATIC CONVEYORS, VACUUM RECEIVER HOPPERS, DISTRIBUTION BINS, INTERMIXERS, GRANULATORS, PELLETIZERS, CONTAINER TILTERS, DRUM TUMBLERS, REPLACEABLE HOPPERS BEING PARTS OF MACHINES FOR DISPENSING MATERIALS, VACUUM AND PRESSURIZED RAILCAR UNLOADERS, PIPE HAULOFFS, AIR FILTERS FOR MECHANICAL PURPOSES, AND LIQUID COLOR INJECTORS