Abstract: There is provided an improved method of cleansing a filter bed utilizing a backwash pump (12) having an inlet line (14) and an outlet line (16). The improved method and system includes two cycle operations. Initially, the filter bed is backwashed to remove contaminants from the filter bed with the backwash pump (12) drawing liquid from an effluent channel (32) through a first diverter valve (18). The fluid flows through a second diverter valve (20) and a first throttling control valve (36) for insert into a backwash shoe (38). In the purging cycle, fluid may be recirculated from the backwash pump (12) through the backwash shoe (38) and then back to the backwash pump (12) with a portion of the fluid being diverted through a second diverter valve (20') into an egress line (42).

Abstract: The invention discloses an improved granular media filter of the type including a filter tank, means for dividing the tank into a plurality of cells, means within each cell for holding horizontal porous support plates, a bed of filter media on the porous support plates, influent means for delivering fluid to be treated to the top of the filter bed, filtrate receiving means in each cell below the support plates for receiving the treated fluid, an effluent channel for removing the treated liquid from the filter, port means for delivering the treated liquid from each filtrate receiving means to the common effluent channel and backwashing means that cooperate with the port means to force a backwashing liquid back through the port means and filtrate receiving means and up through the filter bed for removing contaminants therein and thereon.

Abstract: A process for screening materials as a function of particle size differences by feeding the materials onto one side of a substantially planar screen and vibrating the screen by producing a translational screen oscillation in directions normal to the screen plane and a torsional screen oscillation about an axis normal to the screen plane so that each point of the screen moves in a helical path. Screened material is collected at the other side of the screen and screened retentate is transported by the torsional screen oscillation to an exit port at a location spaced from the axis of torsional oscillation.The process is particularly applicable to shipboard or other mobile use, since the spring stiffness provides good structural support under tilt or side acceleration conditions.