Filter apparatus having filter elements and reverse-flow cleaning means

摘要

A filter apparatus comprising filter elements and reverse-flow cleaning means for the gas filter elements. The gas filter elements can be filter bags, filter pouches or filter cells. The reverse-flow means comprises a two-stage injector for drawing-in clean gas in two stages associated with each filter element by pulses of scavenging gas which are injected into the filter element in the direction opposite that of the filter flow. In order that large quantities of scavenging air for the cleaning of the filter elements can be produced in a small space, the first stage is formed as a Coanda annular slot injector and the second stage is formed as an inlet nozzle. The highest possible kinetic energy in the outlet jet of the first stage is obtained by forming the injector tube of this stage as a cylindrical outlet tube.