Donaldson Membranes have now added their Polyester Epitropic / ePTFE membrane filter media range to their expanding portfolio of certified antistatic products for use in explosive fabric filter applications. EC ATEX Directives require that filter media intended for use in potentially explosive environments must return a maximum electrical resistance of 1×108 Ohms (Ω), both laterally and cross-directionally (across and through the media). In contrast to their already certified products which incorporate Stainless Steel fibres in the substrate of the Tetratex ePTFE membrane filter laminate, the latest developments utilise Epitropic fibres (carbon impregnated Polyester) to provide the requisite conductivity.
Epitropic fibres have long been employed in industrial filtration applications to provide conductivity. However, by re-engineering the product characteristics, Donaldson Membranes are now able to manufacture a product which carries the necessary certification by Dekra Exam GmbH whilst still maintaining excellent filtration efficiency and life performance.
Many dusts handled in fabric filters are inherently volatile and explosions are possible where static charge (within the dust on filter bag surfaces etc) is allowed to accumulate. It is therefore important to rapidly dissipate any such charge to earth and this can be assisted by the employment of the Donaldson Membranes range of antistatic filter media.