Patent ID: 7086405

Claim:
A screenings washer, comprising: a hopper that collects screenings; a grinder coupled to said hopper downstream of said hopper, said grinder directly receiving the screenings collected by said hopper and grinding the screenings collected by said hopper; and a washer coupled to said grinder downstream of said grinder, said washer comprising: an auger rotor that rotates about a substantially horizontal auger rotor axis and that receives the screenings ground by said grinder and transports the ground screenings to a discharge end of said auger rotor, a spray wash system that sprays a wash fluid directly onto a portion of said auger rotor and the ground screenings in contact with said auger rotor while said auger rotor conveys the ground screenings along the rotor axis to the discharge end of said auger rotor, a perforated trough disposed at a bottom of said auger rotor, said perforated trough drains the wash fluid sprayed directly onto said portion of said auger rotor; and a tubular casing directly coupled to the discharge end of said auger rotor, said tubular casing having a severe bend proximate to the discharge end of said auger rotor, said severe bend partially obstructing transportation of the ground screenings transported by said auger rotor so as to form a compaction zone that compacts and de-waters the ground screenings from a substantial portion of the wash fluid remaining in the ground screening after passing the discharge end of said auger rotor; and further comprising a control unit configured to control an operation of said screenings washer in a normal mode operation so that, when said control unit senses a signal indicating screenings are being fed to said screenings washer, said control unit causes said auger rotor to: (1) first, operate in a first forward sequence, in which said auger rotor rotates in a direction that transports the ground screenings towards the discharge end, for a first predetermined amount of time; (2) next, operate in a reverse sequence, in which said auger rotor rotates in a direction opposite to that of the forward sequence, for a second predetermined amount of time; and (3) next, operate in a second forward sequence, in which said auger rotor rotates in the direction that transports the ground screenings towards the discharge end, for a third predetermined amount of time.