The dedusting bag filter Filtrotecnica Italiana sleeves belong to the category of dust collectors and a second employment and needs, can be designed in Different Ways.
In these dust collectors the filter elements are fabric hoses inserted on cylindrical cages made of galvanized or painted steel wire and fastened to the venturi tubes, placed on a tube head, by means of hose clamps. The dusty air comes in under the filtering hoses, passing through the air inlet connection placed on the filter hopper. The Coarse dust falls directly into the hopper. The fine dust remains on the external hoses surfaces. The clean air, passing through the hoses fabric, reaches the top “Plenum” and leaves the filter through the outlet connection. The sequence hoses cleaning is carried out by means of compressed air jets coming from the blow tubes nozzles placed over the venturi. According to the injector principle, blowing the compressed air into the venturi, more air is intaken from the surrounding area. The expansion caused by the cleaning air produces a pressure waves which being propogated all the hoses long makes them shake. The dust previously remained on the filtering hoses, falls into the hopper and hence can be removed. The sequence of the cleaning impulses is automatically controlled by an elettronic timer or a pressure switch and electromagnetic valves. The lenght of the impulses as well as the pauses of the compressed air jets can be easily adjusted if a timer is installed so as to be suitable for the working conditions.
In these dust collector the filter elements are fabric bags inserted on special cages made of strong galvanized or painted steel, fixed on a frontal plate with a tight system. The modularity and the compactedness are the qualities of this filter. The sequence bags cleaning is similar to the hoses with compressed air.
Three series of this filter are scheduled depending on the lenght of the bags:
Series 80 lenght 800 mm;
Series 100 lenght 1000 mm;
Series 150 lenght 1500 mm.
A completely self – contained and compact version is represented by the type FT–TV that is complete with an high efficiency centrifugal intake fan installed on the filter itself. The dimension of the unit is so reduced that the indoor installation is allowed. The filter areas for these types of dust collectors are from 8 to 60 m2. The general operating and cleaning characteristics are identical to the standard model. This type of filter can be supplied with a silencer on the air outlet side or without ventilating section. A special execution insertable type TIV without bags housing and hopper has been designed for the silos or thanks vent installation or to remove dust on pneumatic or belts transport units both with pressurized plant (without fan) or under pressure (with fan). The special construction allows the installation with the bags directly into the silos so that the dust during the cleaning cycle falls inside avoiding additional removing system.
The filtering hoses and bags are normally made of needled felt with fabric picking and are generally washable. The needled felt presents the peculiar characteristics of the felt as well as of the fabric. In fact the felt has a very fine porosity, due to its homogeneous composition, which permits a high cleaning efficiency keeping a good air permeability. The picking fabric inside the felt acts as a reinforce ensuring a high – tension resistance with a minimum stretch. The hoses and the bags can be supplied, according to the temperature and working conditions, with different type of material as shown in the table. Special version like antistatic, with special chemical treatment, with high smoothing finish and flame retardant.