ABSTRACT
Wastewater flows through a screen bar rack to remove large floating objects that could clog pumps or pipes.
Coarse screens or bar racks are usually made of parallel iron or steel bars spaced 2 to 4 inches apart. Fine screens are spaced 1/2 to 2 inches apart.
Screens are usually placed in a chamber or channel at a slanted angle position to allow easier cleaning.
Floating material caught on the screens or racks is removed with rakes either mechanically (automatically) or manually.
Fine screens may use a travelling screen with a spray water system to remove screenings into a trough.
Flow velocity is adjusted to 2 to 4 ft/sec for best performance.
Screens should be cleaned frequently enough to keep water from backing up in the channel leading to the screen which could cause flow surges.
