Static filter systems’ benefits are their costs effectiveness and their ability to utilize a prefilter to protect the downstream final filter.  They are typically used in areas where atmospheric dust is not high and in moderate climate zones. These areas would be coastal regions, rural country sides, and urban industrial zones.  Static systems are also recommended when the air contaminates are sticky and cannot be removed with self-cleaning systems.

The first stage of a static system consists of moisture protection section in the form of a rain or snow hood with the option of a drift eliminator.  If the area were subject to high humidity and/or fog, the moisture protection system would be upgraded to vertical louvers with the possibility of a coaleser pad also.

Downstream of the moisture protection equipment would be the ideal location of any anti-icing heating coils.  This location is selected to prevent hoar frost formation on the filter elements.

The second stage of a static system consists of a prefilter bank.  The prefilters are used to capture medium to large dust particles leaving the fine particles to be filtered by the final filter.  Prefilters are a low cost item so frequent replacement is not an expensive exercise.  AAF has a wide variety of prefilters with varying efficiency ratings and dust holding capacities, which are selected based upon the specific plant’s requirements.

The third stage consists of a set of final filters, which are responsible for removing small dust particles.  Turbine and compressor fouling (or lack of) will be determined by the efficiency level of these filters as these are typically the last change to remove contaminates prior to entry into the machinery.  AAF encourages operators to select high efficiency final filters to maintain high performance levels and reduce the number of water wash cycles required.  Our selection of final filters can provide optimal solutions for efficiency, pressure drop, and dust holding capacity.

In some cases where ultra clean air is desired to minimize water washing, a fourth stage can be employed.  In these cases, AAF can provide our AstroCel III 4000 High Efficiency Particulate Air Filter (HEPA). 

Should a static system’s design incorporate inlet cooling, the cooling system will be located downstream of the filters.  This location is chosen due to the potential for moisture carryover from the cooling medium, which is not desirable in front of the filters.