PARTICLES FOR USE IN APPARATUS FOR MECHANICALLY CLEANING, PEENING AND/OR FINISHING THE SURFACES OF METALS

APPARATUS FOR MECHANICALLY CLEANING, PENNING AND/OR FINISHING THE SURFACES OF METALS AND OTHER MATERIALS AND PARTS AND ACCESSORIES THEREFOR, AND WATER AND WASTEWATER TREATMENT EQUIPMENT-NAMELY, AERATORS AND SLUDGE SCRAPER UNITS

AIR POLLUTION CONTROL SYSTEMS CONSISTING OF PARTICULATE SOLIDS COLLECTORS