They are medium efficiency filters composed of a series of pockets through which the air to be treated passes. These pockets are made in synthetic fibers filtering media (self-extinguish according to DIN 53438) and are properly clamped to a support frame, available also in plastic material. Strong edge weldings ensure the good seal of pockets. The property of these filters is the high filtering surface (proportional to the depth of the bags and their number).
The version with the support frame made of plastic, besides ensuring a perfect seal between the filter media and frame, facilitates the disposal of filters after their use (incinerable).
APPLICATIONS
They are used either as final filters or as pre-filters to high efficiency filters for air treatment units and ventilation plants. Their high dirt storage capacity make them suitable should high dust charge be present.
FEATURES
Their self-supporting capability ensures them to bear any working discontinuity. In order to increase stability pockets with diamond separators are available on request.
The following table shows the filtration class according to EN 779:2012 for the available types, and the nominal capacities with the pertaining initial resistance for some standard available sizes.
| Front dimensions and depth | Number of pockets | capacity [m3/h] | initial pressure drop | |||
| SP 15 | SP 20 | SP 45 | SP 55 | |||
| 592 x 592 x 360 | 6 | 3100 | 40 Pa | 50 Pa | 65 Pa | 75 Pa |
| 592 x 592 x 500 | 4250 | |||||
| 592 x 592 x 650 | 5200 | |||||
| filtration class according to EN 779:2012 | G3 | G4 | M5 | M6 | ||
Capacities comprised between the 75% and the 125% of the mentioned ones are allowed for a good working of filters. Approximately it is possible to consider, inside this range, a linear correspondence between resistance and capacity. The limit working temperature is of 90°C approx.
INSTALLATION & SERVICE
They can be installed into proper holding frames having frontal access and usually designed to fit any possible pre-filters (suggested for SP 55 types).
It is advisable to replace these filters once having reached a resistance of 250÷300 Pa.