Abstract: A double barrel chamber for a media mill where the media mill is used to grind and disperse pigments for paint, coating, ink products, and other pigment-vehicle fluids, as well as grinding and dispersing other particulate matter. Centered in each barrel is a rotatable shaft. On each shaft are a number of horizontally spaced discs. The shafts are parallel and arranged such that the edges of the discs overlap to cause major impacting and mixing in the central portion of the chamber when the shafts are rotated in a common direction. Also disclosed is a coiled cooling water jacket system for cooling a chamber. The system allows 100%, or near 100%, recovery of cleaning solvent, limits potential damage to a pumping system and allows slurry feeding flexibility. A special bearing seal section is disclosed which allows use of a diaphragm pump.