Type EFSTP filter elements of filtration grade STPL are pleated sterile filter elements suitable for FST filter housings of type FWP. They are mainly designed for separating micro-biological contaminants (sterile filtration, dry-type filtration) from compressed air flows, i.e. viruses, bacteria, etc. The filter elements can be sterilised (steaming and autoclaving) and are therefore used for generating sterile compressed air flows (sterile air). Filtration grade STPL filter elements, of course, also separate finest solid contaminants and are therefore used for fine dust separation and to generate ultra clean compressed air flows (ultra clean air).

Type EFSTP sterile filter elements of filtration grade STPL consist of a pleated glass fibre depth filter media, supported by an additional pleated polyester media support inside and outside. The pleated media pack is compactly located between two polypropylene cylinders and end caps and therefore completely integrated in the filter element. All the materials used fulfil the requirements of FDA 21CFR and USP Class VI.

Thanks to the pleating technology the effective filter surface is increased many times resulting in a higher dirt holding capacity and a longer service life. At the same time the flow resistance and therefore differential pressure generated by the filter element is considerably reduced. To avoid a breakthrough at an early stage and to achieve a high number of sterilisation cycles, the pleated depth filter media is provided with a pleated supporting fabric on the inside and out-side. All media are located within the two polypropylen cylinders. In this way, breaking off completely or in parts of the filter layer used for filtration is impos-sible. 

EFSTP..STPL sterile filter elements are manufactured using polypropylene hard-ware and polyester media support and are assembled using the latest thermal welding technology. The welding process ensures a reliable, durable and ther-mal resistant joint of all components and is fundamental to the operational safety of a sterile filter element. There are no resin bonded joints that may soften during sterilisation or break due to different thermal expansions of different materials, both making the integrity of the sterile filter element a risk.

All the features mentioned above are a contribution to a filter element which has a high performance (high separation efficiency) combined with economic efficiency (low differential pressure) and maximum operating safety (integrated, multi-layer, thermal welded design).