Type EFST filter elements of filtration grade A are mainly designed for separating oil vapours from compressed air flows (dry-type filtration). The properties of the activated carbon are especially suitable to separate gaseous contaminants. Filtration grade A is therefore used, if there are no liquid contaminants in the compressed air flow.

The special filter media of the EFST..A filter elements consists of a loose activated carbon granulate, which is embedded between two coarse filter layers. In addition, a separate general purpose filter layer (Z) is located towards the outer side, in order to reliably prevent even the finest activated carbon dust from leaving the filter element. All the functional layers are compactly located between the two stainless steel cylinders and therefore completely integrated in the filter element.

Using loose activated carbon granulate results in, for each filter element, an averagely large amount of activated carbon in relation to the filter surface (1.2 kg activated carbon for each m² of filter surface). This considerably increases the separation capability and the service life. The 3-layer design contributes to an adequate thickness of the activated carbon bed and thus to a contact time between compressed air and activated carbon, which is long, compared to filter elements. 

Thanks to this layer design the differential pressure achieved by the EFST..A filter elements is amazingly low. The general purpose filter layer downstream of the activated carbon usually eliminates the need for additional downstream filtration. All media are securely located in the two stainless steel cylinders. In this way, a breakthrough, completely or in parts of the filter layers used for filtration is impossible. 

All the features mentioned above contribute to a filter ele-ment which has a long service life (high adsorption capacity) combined with economic efficiency (low differential pressure) and maximum operating safety (integrated design). This guarantees an extremely low residual oil content.