Coal-water slurry producing system

Claim 1

A coal-water slurry producing system comprising: a continuous type ball mill comprising a rotatable cylindrical mill with an inlet and an outlet, respectively, provided at each end of the mill and arranged at a rotational center of the mill for grinding coal with water and additives to produce a coal-water slurry; a rotatable screen apparatus disposed at said mill outlet to remove coarse coal particles contained in the coal-water slurry produced by said ball mill, said screen apparatus comprising a slurry inlet port connected to said mill outlet, an outlet port for coarse coal particles provided on a side opposite to said slurry inlet port and a cylindrical metal screen disposed between said slurry inlet port and said outlet port and adapted to pass the coal-water slurry containing coal particles other than the coarse coal particles therethrough; strainer means for removing coal particles of a predetermined size and above from the slurry, said strainer means comprising a stationary outer casing, an inlet provided in said outer casing for entry of the slurry, a screen for filtering the slurry, a product outlet provided on one side of the metal screen for discharging filtered slurry from the outer casing and a returning outlet provided in said outer casing on another side of the screen to discharge the non-filtered slurry; feeding means for feeding the coal-water slurry from said screen apparatus to said inlet of said strainer means; delivery means for delivering the coal-water slurry filtered by said strainer means from said product outlet of said strainer means to a slurry storage tank; first returning means for returning the non-filtered coal-water slurry to said mill entrance; and second returning means for returning the coarse coal particles removed by said screen apparatus to said mill entrance.