An approximate theory for stresses in dust cake of ceramic candle filters

A simplified theory is developed that yields the approximate stresses within a dust cake on the outer surface of ceramic candle filter and gives the critical factors which ensure complete detachment of cake. The radial and tangential stresses in cake during filtration have been derived by consideration of active state of stress in the dust cake. Back pulses of cleaning gas expand dust cake on the condition, that their power is just adequate to properties of cake, such as angle of internal friction and cohesion. Expansion of the dust cake induces tension cracks and disintegration of the cake. Back pulses of higher values hamper expansion of cake and cause “patchy” cleaning.

Dust cake expands under reverse pulse of gas and a narrow gap exists between the cake and candle. There are tension cracks penetrating through the dust cake completely. If efficient cleaning is required, the dust cake should be divided by tension cracks into segments which could be easily blown out from a candle.Figure optionsDownload as PowerPoint slide