Baghouse and Cartridge Filters Working Principles

Baghouse filters and cartridges filters work thanks to the filtration principle by micro-perforated textile, made in the form of cylindrical bags or pleated cartridges that are fixed to the filter structure and supported by metal cages. 

The air charged of dust is suctioned in the hopper or directly in the filter body by means of an aerodynamic inlet duct designed to obtain a uniform distribution of the gas. At the entrance of the filter there is decrease of the gas speed, as well as a change direction of the gas flow, that provokes the precipitation of the biggest particles. 

The flow is distributed on the whole filter elements surface, crossing them from the outside in. Once filtered and cleaned, the air is conveyed to the filter outlet and then canalized to the funnel. The dust settled on the external surface of the filter elements produces a uniform layer that facilitate the filtration, increasing gradually the pressure drop.

A periodic cleaning of the filter elements by a strong air blast is done because it is necessary maintain the pressure drop within balanced limits. Each filter element has a sleeve by which high pressure and speed air is injected. This produces a wave that detaches the dust layer from the external surface of the bags or the cartridges. At the same time, the compressed air blast makes the venturi produce an upstream air flow that guarantees the cleaning of the fibrous layer. 

The regularity and duration of each cleaning are managed by a signal that act on the electrovalve of injection of the compressed air, that in turn acts on a line of sleeves. Everything according to the instant value of the filter pressure drop.  

The dust, detached from the filter element surface, is collected by gravity in the hopper and then discharged into the bin. The discharge can happen continuously thanks to the action of the rotary valve or the rotary valve together with the screw conveyor.