Abstract: A slurry pump (40) pumps a slurry of vulcanized rubber pellets and water from a slurry mixing region (30) to a mill (B). The slurry passes through a comminuting zone (80) defined between an abrasive stator (66) and an abrasive rotor (76). As the slurry is comminuted in the comminuting zone, heat is generated, which heat is absorbed by at least the water. The comminuted rubber particles and water pass from the mill to a separator (C) which separates the rubber particles from the heated water. The heated water is conveyed to a hot water reservoir (24) from which it is recirculated to the slurry mixing region. Additional pellets from a pellet supply (10) are fed to the mixing region to be mixed with the recirculated heated water. In this manner, the slurry is preheated above room temperature prior to comminution. It has been found that increasing the water temperature to about 130.degree. F. rather than using city water of about 55.degree. F., increases the production rate of the mill by about 20 to 25 percent.

Abstract: A pellet feeder (A) feeds pellets of vulcanized rubber or other materials and water or another fluid at controlled rates into a mixing tank (30). An agitator (32) mixes the pellets and fluid into a slurry. The slurry is pumped from the mixing tank to a mill (C) by a pump (34). The mill has a receiving region (70) defined between a stator (48) and a rotor (68) for receiving the slurry. The stator and rotor define a peripheral grinding zone (72) around the slurry receiving region. An impeller (74) has vanes which extend from the upper surface of the rotor to an abrasive surface (82) of the stator such that the impeller vanes are ground at the same rate as the stator and rotor wear to maintain a fluid seal around the impeller blades. Fluid cylinders (50, 52) maintain a constant pressure between the stator and rotor. The stator has a plurality of recesses (86, 86') which preferably have downstream extending relief areas (214).

Abstract: A pellet feeder (A) feeds pellets of vulcanized rubber or other materials and water or another fluid at controlled rates into a mixing tank (30). An agitator (32) mixes the pellets and fluid into a slurry. The slurry is pumped from the mixing tank to a mill (C) by a pump (34). The mill has a receiving region (70) defined between a stator (48) and a rotor (68) for receiving the slurry. The stator and rotor define a peripheral grinding zone (72) around the slurry receiving region. An impeller (74) has vanes which extend from the upper surface of the rotor to an abrasive surface (82) of the stator such that the impeller vanes are ground at the same rate as the stator and rotor wear to maintain a fluid seal around the impeller blades. Fluid cylinders (50, 52) maintain a constant pressure between the stator and rotor. The stator has a plurality of recesses (86, 86') which preferably have downstream extending relief areas (214).