Backwash method and apparatus

摘要

The method and apparatus for filtering a liquid including a filter vessel divided into an upper filter compartment and a lower plenum compartment. An external vessel is positioned at or below the elevation of the tops of the filter element fittings in the plenum compartment. A pressurized gas is supplied to the upper portion of the external vessel forcing backwash liquid from the external vessel into the lower portion of the plenum compartment backwashing filter elements within the filter compartment.