Pneumatic conveyors and parts thereof, mechanical type dust filters for building dust control systems, cyclone separators for particulate matter and parts thereof, airlocks for pneumatic conveyors for conveying dust and other particulate matter, particle grading and classifying aspirators for separating particulate matter and fines from grain and other granulated materials for use in particulate milling equipment, fans and blowers for pneumatic conveyors, bran finishers for separating flour particles from bran, stream splitters and spreaders for mixing and spreading grain and other granulated materials for use with milling equipment