Machines and mechanical devices and installations composed of the aforesaid goods for mechanical process engineering, namely, mills, crushing machines, classifiers, air classifiers, classifier mills, compactors, mixers, particle rounding machines, machines for producing functional particles, compactors, recycling machines, dust separators, cyclones, mechanical dosing devices, mechanical discharge devices; parts for the aforesaid machines and mechanical devices, included in this class; machines and mechanical devices and installations composed of the aforesaid goods for processing plastics, namely, tubular film extruders, film blowing heads, mechanical film take-offs, film winders, screen changers, film stretching systems, blown film cooling systems, film calibrating devices and film calibrating systems assembled therefrom