Bag filters are dust removal devices for the dry separation of solid particles from polluted air or gas, which can be applied in all areas of industrial production.
Description of Filter Function
The gas containing solid polluting particles enters into the lower part of the hopper or into the side part of the bag filter box where, as a result of a decrease in the gas flow speed, the coarse dust particles are initially separated. The polluted gas moves further up to vertically suspended filtering hoses through which it passes into the clean gas plenum chamber and subsequently comes out of the bag filter.
The dust particles stick to the surface of the filtering hoses and create a break-free film of dust, which is regularly removed by pulse regeneration. The actual regeneration is carried out by short pulses of compressed air that is blown into the internal parts of the hose from openings of the washing tube through the Venturi tube. As a result of compressed air pulses acting on the internal side of the hose, the settled dust layer is detached from the external surface of the hose. The dust gradually falls into the hopper from where it is carried away, through the hermetic closing device, outside the bag filter space.
The frequency and length of compressed air pulses are ensured by membrane valves that are controlled by a control unit through solenoid valves. On the basis of bag filter pressure loss or fixed time mode, the regeneration process is controlled so as to prevent an excessive increase in the pressure loss and to maintain a permanent layer of dust on the filtering hoses, a so-called “filter cake”, which increases the filter effect of the bag filer.